Notes on the Hornady 366 auto shotshell
reloading Press:

Part I:     Introduction, mounting set-up, powder/shot bushings discussion for 
               loading legal Int'l trap and skeet shells recommended spare parts.

Part II:    General problem solutions/tool adjustments for best results.

Part III:   Some reasons and solutions for poor quality crimp results. Includes 
               a special section on 410 bore skeet reloading.

Part IV:   On changing dies to a different gauge, setting up a new die head or just
               checking to insure the 366 is in proper adjustment.

Part V:    The 366's annual maintence.

Part VI:   Some thoughts on the buying of a used 366. Also includes the essential tool and                            recommended spare parts lists.

Index:

Disclaimer:

366 gauge changing:

Setting up a new die head:

Setting the resizing station #1A:

Deprime punch adjustment #1A:

Setting the deprime only #1:

Setting the primer seater #2:

Setting the primer drop tube:

Setting up the wad Seating #4:

Setting the crimp start die #6:

Setting the final crimper #7:

Setting the crimp taper #8:

Final comments:

Disclaimer/Safety Cautions:

This article is mainly written for those who have owned 366's for while and are interested in possibly picking up some tips, or otherwise experienced loaders looking for information on the Hornady 366 auto shotshell reloading press. Use of the information is at your own risk. These notes come from nearly 40 years working with the Pacific/Hornady 366 reloading tool; others will have had different experiences. If you are not an experienced reloader, please, please, please buy the several excellent books that are on the market and become intimately familiar with the process and the very necessary safety procedures. Reading the MSDS statements available on the various manufacturer's websites provides valuable information as well as the powder recipe booklets forewords. These booklets are available either by download or by mail at no charge to the requester. Many of those sites offer how-to-reload information as well. Always follow exactly the loading recipes supplied by the propellant manufacturers. Reloading is not a place for short-cuts and sloppy guesswork. And obviously, you cannot safely reload with best quality when you are tired, in a hurry, or otherwise not able give your full and proper attention to the job.

Two current shotgun reloading information books come immediately to mind: Lyman 5^th edition Shotgun Reloading Manual is one. Another is the Reloading for Shotgunners,fourth edition by Kurt D. Fackler and M.L. McPherson. They are available from www.amazon.com, where you buy components or any good sporting goods store, online or not. MEC and RCBS ("The RCBS Handbook of Shotshell Reloading") also offer shotshell reloading instruction manuals at a reasonable price. Better yet, in addition to the books, find someone who is a well-experienced reloader to help you get through the learning stages explaining what the books may not make clear to you and who can answer the occasional question that comes up from time to time.

All parts descriptions are found in the current Hornady manual, Page 23.

You can download the latest manual (PDF) from Hornady here.

366 gauge changing:

The 366 offers rapid gauge change between 12, 16, 20, 28 and 410 bore. Changing gauges can be done in two ways. A die set kit can be obtained and used with the current loader. The downside is that time must be allowed for disassembly of the current dies and an adjustment period to tweak in the new die setting for perfect shell output. If a gauge change is needed only occasionally, it's the way to go.

(Note: the 16 gauge die set is not available at this time and for whatever the reason, Hornady also does not currently offer a specific 410 die change kit. It likely can be parted out or the first 366 can be acquired in 410. See the special section on 410 reloading for more. Possibly, the 16 and 410 dies could be found on ebay or on trapshooters.com.)

If frequent die changes are desirable, the 366 design also provides for a very rapid change-out to a alternative die head with dies already pre-mounted and set up for the new gauge. Going this route means that within 5 minutes the 366 can be changed over to the new gauge and you can start loading. Within gauge, as between target or hunting loads, a bunker first barrel shell vs. a second barrel shell, or a sporting clay close-shot load vs. a long distance load, using radically different component sets, it's less than a minute as the shell plate, ring and the wad guide do not have to be changed. Again, no adjustment period is needed to tweak in the dies, maximizing loading time.

Changing dies, setting up a die head; station adjustment:

If you are just changing dies, first remove the old dies and install the new ones that come in the new die set. Initially, it is probably wise to loosen the locking nuts on the primer drop, primer seating, Crimp start/pre-fold, Crimp taper/TaprLoc stations and leave the final crimp die out for now. The resizing station setting should be okay needing only a quick check to insure no change has occurred; you don't even have to install the new resizing ring—if you're not going to use it. 

Having the right tools makes the work go easier. You may want to look over the this list of essential tools for the 366. 

If you're not setting up a die head, click here to jump directly to the station adjustment section.

Setting up a new die head:

A completely set-up and adjusted 20 gauge die head (Wad guide, shell plate and shell plate ring not shown.). Note that the measure attachment bolt, station #1 deprime punch and probably even the crimp taper (TaperLoc) die is optional. For a complete die head assembly, you will need several parts in addition to the die kit. Here is the the supplemental die head parts list.

Pic of the assembled die head with supplemental parts, ready to add the die kit components.

In final assembly of the new die head, ensure the resizing spacer, primer drop tube, primer seater wad,pre-fold and taperloc dies are well up into the die head. It is best to not install the final crimp die now. All locknuts should be quite loose.

Station adjustments:

(If it's in place, you may want to remove the measure casting assembly for the adjustment process to make things go easier.)

Resize and De-prime station (Station #1A):

After installing the new head, all adjustments start with station 1A, the resizing/depriming station (even if you don't plan to use it); the remaining stations cannot be properly adjusted until this is correctly set. To begin, ensure that the size die lock nut is quite loose, with the die body screwed up into the die head so that when the handle is bottomed, there is a rather large gap to the platen casting. The resizing ring must be tight. Bottom the handle, then move the die body down so that the resizing ring is a bit short of the plate. Move the handle to the top position and insert the hull to be deprimed, and bring the handle down to the bottom. This is an iterative process; you can expect to need multiple adjustments until it's perfect—have patience! When things are adjusted right it will look as in the following picture:

Note the resizing ring is smack on the plate when the operating handle is at the bottom.

(This is good time to get the feel of handle bottoming if you haven't already. Everything flows from getting this feel so that you can know that you've done it properly and that no issues have arisen with the resizing, primer seating, wad insertion or crimping actions. A problem occuring at each station will transmit a different sensation to the operating handle. This fact will enable you to instantly realize problems when wads are catching on the hull mouth in the wad insertion station or, when hulls are not resizing properly, and even when shells are not crimping properly. Learning that feeling is the key to successful 366 operation that produces perfect shells.)

Now that you've got things set, tighten the size body locking nut and re-confirm that the size die ring cap (resizing ring) is still tight. Resize another hull or two and recheck everything to insure things are still looking good and things didn't change in the tightening-up process.

De-prime punch adjustment (#1A):

(B) The size die eject bolt needs to show at least 1/4" (6.5mm) from the (A) deprime punch guide. In this threaded-down position, a nut will likely be needed to lock the de-prime punch guide in place. Test with the hulls you will be loading to insure the primer always gets knocked out.

If it is more comfortable for you to have the hull eject at a higher part of the up-handle movement—and you never reload hulls with high "brass" (greater than 16 mm the hull will not eject)—the deprime punch guide can be threaded up to the stop.

De-prime Only station (#1):

This station (#1) is very useful if your experience has shown that the hulls from your specific gun chamber effortlessly without resizing the shell brass (A potentially significant downside of not resizing is if you need to use a different gun at the range and your unresized shells now no longer reliably chamber). In 28 gauge and 410 bore, a flaring sleeve is added to open up the case mouth further to expedite wad insertion. Not resizing hulls saves a noticible amount of operating handle effort.

(Of course, if it's the least effort you want, try some brand new, primed, Fiocchi cases. There's an astounding drop in effort when you don't have to resize, de-prime and re-prime. You'll need the MEC metal crimper—see Part II. The 12 gauge plastic crimp pre-fold die doesn't work worth a darn here.)

If you don't use it, no de-prime punch needs to be installed. It sometimes is an inconvenience when a hull slips out of the indexing disk and the de-prime punch jams in it.

If you're loading 410 or 28 gauge, (it's usable in 20 gauge as well), Hornady provides a flaring sleeve (case mouth opener) that slips onto the de-prime punch. To adjust, slip up the flaring sleeve to the bottom of the punch mounting threads and tighten the 3/32" allen head screw. Loosen the punch's locking nut and thread the punch up into the die head enough to insure the flaring sleeve won't spread the case mouth open, then iteratively adjust the punch down with an average length hull in place until the hull mouth is opened just short of perfect, then tighten the locking nut.

This is another case of variable hull lengths being an issue: a longer than average hull can possibly have the case mouth cracked open along the crimp fold lines leading to shorter case life. The older the hull, the more likely this will be an issue. Conversely, shorter hulls will not get the case mouths opened fully. If you load mixed-lot hulls, you likely will have to re-adjust flaring sleeve height for each case. See pictures below.

The flaring sleeve was set to an average-length 66.40 length hull (right picture). As you can see in the left picture, a too-short hull is barely opened (note the exposed dark band), while the center picture shows the longer hull's case crimp lines starting to split.

In practice, it may well be better to not use the flaring sleeve at all and manually use a tool (perhaps from ballisticsproducts.com or precisionreloading.com) to open the few cases you need to open up as the alternative is to measure every hull, sort to length and batch load unless you use hulls from the same lot. You probably won't need the flaring sleeve on new hulls, but as the case comes to end of its reloading life, the case mouth tends to fold in making perfect wad insertion sometimes challenging at the wad seating station.

Primer seating station (#2):

The next step is the primer seating station (The primer drop station is set after). Again, confirm the primer seating punch is high enough so that the primer cannot be seated and that the locking nut is quite loose. Move the resized/de-primed hull from the resizing station to the priming station. Insert a fresh, unresized hull into the resizing station. You may find it useful to put a mark on the primer seating ram so as to keep track of the rotation amount.

Bring the handle down, then up a bit and you should find the hull cannot be moved out of the priming station as the primer is not seated. Adjust the seating ram down in 1/4 turn adjustments until the primer is seated exactly flush.

If you are using the 12 gauge optional accessory spring loaded seating punch (Hornady part #010051), you will need to be using the deepest hull for this set up, usually a Remington hull. This ram requires extra effort (muscle!) when loading higher basewad hulls, as AAHS, because you are pushing against the spring. A tiring disadvantage in those long 500 to 1000 shell loading sessions! And you lose the ability to precisely seat the primer to the exact spot with the least effort. That's the advantage of the standard ram. But if you like the flexibility of mixing hulls, the spring loaded seating ram is the way to go.

Primer drop tube:

Put 10 - 15 expended (dead) primers into the tube and with hulls in the resizing station and primer seating station, bottom the handle. The primer should not drop. Initially, adjust the drop tube (primer feed body) 1/4 turn or less at a time—when you are very close, just creep up on the final adjustment—until a primer drops perfectly every time. The primer feed stop unit fingers should look like this:

Note the primer feed body tube itself is just at the plate and the primer feed stop unit fingers are rather bowed out. The tube setting needs to be very precise: a bit too high and occasionally a primer will not drop; if the tube actually is hitting the plate, it will develop a primer drop-stopping burr and you will have to stop everything, remove the tube and use a small 1/2" hand reamer, small half-round file or the like to remove ithe burr, then go through the adjustment process again. When set, tighten the lock nuts up and re-test a few times to insure things are right.

Powder Drop Station (#3):

There is no adjustment to the powder drop station, other than to confirm it's free to move, so it's on to the wad guide station.

Wad seating station (#4):

There are two points of concern when setting up this station: height, and sufficient rotation of the guide to allow easy wad insertion. For height, it needs to be high enough to clear the longest hull you might reload. Be very much aware that hulls are not length-consistent. One brand of 2 3/4" (70mm) hull will be different than another and the lengths will vary from lot to lot within the brand. 12 gauge Winchester AAHS are pretty good in consistently being about 67mm +/- about 1 mm. Federal Gold Medal and Fiocchi seem to run +/- 0.5 mm. Cheddite hulls are even better. Remington hulls, on the other hand can be as short as 65 mm (Gun Club) or as long as 72 mm (Gold Nitro 27's). Other gauge hulls are no different. Hornady recommends 1/8" clearance from the hull to the bottom of the wad guide. If your hulls are relatively length consistent, this can be reduced to 1/16". A smaller gap seems to help minimize wad insertion problems.

Using a long 1/4" (6.5 mm) flat blade screwdriver or better yet, a 5/16" (7.5 mm) nut driver (Unless you've changed the screw to an allen head!), loosen the back nut and slide the wad guide so that the bottom of the guide is 1/8" (3.5 mm) above the case mouth of the hulls you are using. With the handle fully vertical, rotate the wad guide toward the front about 35 degree. and tighten down the screw. Recheck that the height did not change.

The wad ram length need only be set so that the wad is just setting on the powder. This setting will also insure that shot does not fly out when the index plate is rotated. It can be set for wad pressure, as in some component combinations that seem to need a bit of wad crush to get satisfactory crimping, but for cosmetically consistent crimping it is better to use a slightly shorter wad or a less bulky powder.

One thing you may find is that with true 12 gauge 24 gram wads, you might have an issue where the wad guide swings back to home only to see the wad petals hit the wad guide ram, even when the ram is threaded up to the top. One simple solution is to take the wad ram out and grind it down about 1/16" (2 mm). This will also relieve an excess wad pressure problem.


Hornady recommends the gap between the hull and the wad guide be about an 1/8" (3.5mm). When loading assorted Remington hulls, this is certainly proper advice as there is considerable length variation: between Gun Clubs and Nitro 27's the gap can be more than 7 mm (1/4"). Remember that the skeet 410 is a 2 1/2" length hull and the wad guide height should be changed when moving the 366 to/from this shell length.

With AAHS, Federal GM, Cheddite and Fiocchi hulls, the gap can be smaller as their case lengths are much more consistent, usually within 1/32" (1 mm). the hull—wad guide gap in above photo measures about 1/16" (2mm). A smaller gap seems to help minimize the overpowder cup of the wad catching on the case mouth.

One other thing is to confirm that the wad ram is not pushing on the wad before the wad guide is seated on the hull. This will decrease the likelihood of the overpowder cup catching on the case mouth. Adjust the wad ram as needed here. Also, see adjusting the small gauge wad rod spring.

On sufficient rotation of the wad guide:

About 30 - 35 degrees is a nice compromise for ease in popping the wad into the guide. More angle means more effort to move the guide out when moving the handle to its upper stop.

Adjusting the small gauge wad rod spring

This spring is used in the small gauges to stop the wad rod, forcing the wad guide fingers into the hull's case mouth. This action helps minimize the problem of the wad's overpowder cup catching on the hull mouth when the wad ram starts to move the wad into the case. See picture to the right. Note the wad guide fingers are inserted into the case and the wad ram is just about to start pushing the wad down into the case.


Adjustment of the spring is done iteratively, bending the spring just a bit each time with pliers until the least amount of rod pressure possible is found that will stop the rod's movement. It is strongly advised that a dab of grease be applied to the spring to make things a lot easier to move.


Sometimes, it's worthwhile to install the spring in 12 gauge when you have some hulls with slightly closed case mouths.

Shot-Drop station (#5):

Like the powder drop, there is no adjustment to the shot drop station, although it's a good idea to confirm the drop tube is free to move in the smaller gauges.

Crimp start/pre-fold station (#6):

Measure and select a few hulls to set up this die with hulls of an average length from the lot you are loading. Resize them to insure no binding in the index ring, then put it into the station. Ditto for the priming station and the resizing station. This maintains height. Ensure the pre-fold die is on the high side and that it is completely free to spin like a top to insure it will find the hull's crimp folds without fail. If it's binding, clean the crimp starter bushing with a Qtip and lubricate with graphite.

In an iterative process, lower the handle, bottoming it while adjusting the crimp start die down until the crimp shows a 1/4 " (6.5mm) opening. It is better to leave the die set for a bit more pre-fold than less. Tighten the lock nut down. Now test a couple of more hulls to be sure that the die did not move in the tightening process. Any inconsistency not caused by improper bottoming of the handle will likely be caused by hulls of different lengths. Minor hull length variations (1 mm) won't be a problem unless you want perfection. Using average-length hulls from the lot you are using will prevent circular adjustment frustration.


Classic example of the correct amount of 12 gauge prefold shown on left; 1/4" (~6mm) pencil fits perfectly. AAHS, Remington's can take more prefold if needed to compensate with final crimp issues... Hull on right is prefolded to 3/16" (4.5 mm). This is probably the maximum prefold usable without creating side-bulge issues—in AAHS or Remington cases. As you would expect, the prefold dimension is gauge dependent; 20 gauge measures about 7/32" (5 mm), 28 gauge about 5/32" (3.5 mm) and the 410 bore is about 1/8" (3 mm). Remember, these are just the initial gaps and may well need to be tweaked for perfect crimps.

Right photo: Reifenhauser hull example. Max prefold before side crimp bulges. Note nice smooth line.

Reifenhauser hulls are sometimes difficult to get enough prefold in for a perfect crimp. For a possible work-around, after setting the crimp start die for maximum pre-fold before getting side crimp bulges, backing out the crimp plunger and threading the die body into the die casting so that less threads are exposed. The limit is when the case crushes, perhaps when about 8 - 9 threads are exposed. This adjustment seems to help with some Reifenhauser hull plastics. . .


Having SAAMI-spec sized shells is especially important to (bunker) shooters exiting station 5. If you don't fire the second barrel, you need to get the shell out of the chamber quickly to keep the squad moving—and yourself safely and legally unloaded to station 1 ASAP. It's not pleasant being forced to stand there trying to pry a stuck live shell out of the chamber so you can safely leave for station 1.

Final Crimp station (#7):

For the final crimp station adjustment, resize a hull, put a dead primer in it and using your scale, weight out the powder and shot charges you are planning to load, load them into the hull with the selected wad in between and put the shell into the pre-fold station. Again, place hulls into the primer seating station and resizing stations, then pull and bottom the handle so that the test crimp shell gets pre-folded. Confirm that the pre-fold has a (in 12 gauge) 1/4" (~6.5 mm) gap.

Move the shell to the final crimp station. Set the final crimp die up so that the crimp plunger is flush with the top of the nut. and screw the die into the die head. As before, iteratively move the die body down a 1/4 turn at a time until the crimp is at the perfect depth. Tighten the die body locking nut, then run two more shells through to confirm the setting. The crimp progression should look something like the following:

(A) partial closure. (B) not yet quite there, and (C), perfect, flat crimp. Final frame (D), shows a too-deep crimp. If this occurs consistently, try using more pre-fold. If this doesn't work out, then the shell components are too short and need to be made longer, usually with a slightly longer wad. Might also be worth checking shot weight and powder drop.

On setting the final crimp depth:

A careful search of the literature shows most findable recommendations state the crimp depth should be 2/32" (1.6mm, or 1/16" or 0.0625" or roughly, the thickness of a USA dime coin: 0.055" or 1.4 mm). Presumably, the recipes that we follow all used this depth to determine pressure and velocity levels. Some manuals suggest to set the depth to match that of a factory loaded shell. Unfortunately, the crimp depth in factories seem to vary lot to lot (and from loader to loader).

Using this 2/32" depth of crimp will presumably duplicate the results of the testing lab. But most loading data manuals don't state that. Hodgdon produced a test many years ago showing that the effects of setting crimp depth significantly different from a/the nominal 2/32" can result in surprising—and possibly unsafe—changes in pressure and velocity. Tom Armbrust's article has this data (Crimp depth section is about 1/2 way down the page). Same material is more colorfully presented on pages 16 and 17 of the Hodgdon Powder shotshell data manual, 1st edition, if you have access to a copy. Tom Cerullo also has a nice crimp depth article discussing this in the TrapshootingUSA magazine archives and shows the same test data. Additionally, there is a nice discussion of the importance of crimping on page 2 in the latest Accurate powder manual by ballistician Johan Loubser, altho no crimp depth dimension is offered: Accurate v.2.1 loading manual. And finally, in earlier reloading manuals, Scot powder (now owned by Accurate) specifically called for the 2/32" crimp setting, along with many very informative recommendations on making safer and better reloads.

A simple, quite accurate, crimp test depth tool can be made by grinding a crimp-sized notch into one side of the jaws of an electronic caliper. The depth then is the difference between the overall cartridge length and the length measured to the crimp. Convex crimps throw the measurements off though. The tool offers increased accuracy over the somewhat awkward ruler-at-the-crimp method.

Crimp taper/TaprLoc station (#8):

This is an interesting station. The crimp taper or TaprLoc station as it was called in earlier 366 manuals, is intended to slightly taper the last 1/2" of the shell to insure easy chambering, particularly when the shell is intended for use in auto loaders and pumps. It can also be used to put a round on the case mouth. However, most factory shells do not have a significant roll; that suggests that long experience by the factories shows it's not really necessary.

Since many shooters use over/unders, it's practical to not use this station and the additional physical effort that it requires on the operator to get that tapering. Usually, this station is more trouble than it's worth; not using it saves effort.

While the 12 gauge crimp ("paper") die measures 0.691 at the mouth and 0.671 at the bottom of the die, it doesn't seem to have that much effect on loaded plastic shell case dimensions in use. The Lyman 5th edition handbook drawing on page 405 of the maximum 12 gauge cartridge diameter specs the maximum diameter to be 0.797 – 0.020. New AAHS cases load to about 0.790 using the latest Hornady Final crimper (If you have the old black anodized crimper it is well worth the price of the new crimper in improved quality crimps. It's available in both 12 and 20 gauge). Using the crimp taper die showed variable results to the diameter, sometimes actually making it larger, sometimes smaller. However, the case plastics are sensitive and different case plastics deliver different results. 

Setting up the die:

Initial taper adjustment: measure down 1/2" (13 mm) from the a loaded shell's crimp and put a line on the shell. Bring the die down until the end of the die is just before the mark. Slowly bring the die down a small amount at a time while bottoming the handle until resistance increases. Back the die off. This will give you the maximum tapering allowed by the die. You may want to measure the shell mouth diameter of several shells before and after TaprLoc use to see if it's worthwhile to continue using this station with the shells being loaded. The best way to take the measurements is with digital calipers as the differences are usually only a few thousands.

Locking down the locknut is hard on this station as it is difficult to get a wrench on the nut. A smaller dimensioned 7/8" open end wrench works best. Crescent wrenches are much too large.

Final Comments:

This completes the initial adjustments. At this point, you are ready to begin the reloading cycle. You should be alert to any tweaks necessary on the first few shells through the 366. It's probably wise to check the lengths of the hulls used initially—finding ten average-length hulls is likely enough—to insure the lengths are reasonably consistent with the average hull length of the lot you are loading (the fastest way to check hull lengths is with an inexpensive digital caliper).  This precaution will prevent you from getting into a circular adjustment cycle where you compensate for an off-length hull, only to be mis-adjusted for the rest.

This completes the four part series on loading with the Hornady 366 loader. Hopefully, it has been able to help answer a question or two along the way.

Since there are always problems that I have never or rarely experienced (for example I don't use the auto-advance or gas assist features so I cannot comment), I would be glad to add further suggestions and solutions or hear comments. Email: admin@bunkershooter.com.

(I don't use the auto advance as I quickly found that I had to be careful to raise the operating lever smoothly in order to insure the primer dropped into the priming station. Harder-to-resize steel-base hulls made this difficult. Since my original 1971 366 didn't have the auto-advance and I had loaded tens of thousands of shells without the auto advance it was easy for me to go back, and operate without it after acquiring machines that had it. I also found the auto-advance would occasionally get out of adjustment and I had to adjust the back bearing and/or pawl assembly. Removing it meant one less thing to go wrong during those I-gotta-load-500-for-the-weekend sessions and less effort on the operating handle's upstroke. With the AAHS's ease of resizing perhaps I wouldn't have given up on it as the hulls come out with little effort from the resizing die making it easy to smoothly drop the primer.)

End part IV, 40 years with the Hornady 366.

Link to Part I: Introduction

Link to Part II: General problem solutions

Link to Part III: On poor crimps; 410 reloading

Link to Part IV: Changing gauges

Link to Part V: Annual maintenance

Link to Part VI: On buying a used 366

Link to the home page

Thanx to Chuck Dietl for reviewing and sharing his comments to make this series better.

Appreciation is extended to Ryan Vijil for the inspiration to write this series.

As always in America in these times, use of the information above is at your own risk.

A final note of appreciation and a big thanks to Hornady for keeping the 366 reloader in production and parts easily available!