T he following is a summary of what I've learned about the 24 gram bunker/Olympic trap (and skeet) load since 1991: Other experimenters may have realized different results. A lot of averaging is done in the shotgun game. . . A bit of trivia: The 36 gram (1 1/4 oz) era ended in 1973, 32 gram (1 1/8 oz) era ended in 1988, 28 gram (1 oz) era ended in 1990 with the current 24 Gram (7/8 oz) era starting in 1991.

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. Always follow exactly the loading recipes supplied by the propellant manufacturers. Any questions may be asked on the product support lines. Reloading is not a place for short-cuts and sloppy guesswork. 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 books come immediately to mind. The 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 (RCBS: "The 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. You will also find that Hornady's tech support is second to none and will be of tremendous help. They're just plain good people!

Some better performing 24 gram bunker/ISkt component sets:

These have shown themselves to perform very well over a chronograph and on the pattern board. They make a good starting point for a reloading choice delivering excellent crimps and patterns.

Remington Gun Club hull, Remington 209P primer, Hodgdon's TiteWad, Winchester Gray WAA12L wad and Black Diamond 7 1/2s. STS and Gold Nitros will work nearly as well.

Winchester AAHS hull and primer, Red Dot/PROMO powder, Claybuster CB 1100-12 (Claybuster 12SL equivalent. Wad gives the most consistently perfect crimps of any when used with the bulkier powders, such as Clays or Red Dot.) or Winchester/Claybuster 12L. The latter delivers best crimps when Hi-Skor 700X or TiteWad is the preferred powder. The Claybuster 12L delivers the softest recoil.

Fiocchi or Cheddite hulls and primers, Red Dot/PROMO or SOLO 1000 powders and the economical Downrange orange XXL (Downrange literature says this is a 12S0 substitute), or Bascheri & Pellagri T2/Gualandi REX wads.

Some complete sample pattern run results are here: 24GramPatterns (48k PDF).

Loading data is available from Accurate, Alliant, Hodgdon, Ballistic Products and Precision Reloading as appropriate.

On the softest shooting load:

In a tapered plastic case, using the CB078 wad notably seems to be the softest recoiling. Alliant E³, Clay Dot and SOLO 1000 are the softest, smoothest, shooting powders. For some, this may be a softer recoiling load than a load developed in a paper case as the recoil is more quickish. 

A comment on shot selection for first and second barrels:

In the 36, 32 and even 28 gram eras, many shooters would mix loads, putting 8's in the first barrel, with 7 1/2's in the second. Remington-Peters made it especially easy with color ID'd blue-hulled Peters 8's and green-hulled Remington 7 1/2s (or visa-versa). The smaller 8-sized shot has plenty of energy to break the first-barrel target for all but the slowest shooters and the intrinsically 10% higher pellet count sweetened the fringe to break a target when the shot placement was less than perfect. A further refinement is to use a first barrel shell with a bit less velocity to better keep you in the gun for the second shot, if needed.

Today, handloaders can use the Winchester red and gray cases to the same advantage to keep the loads separated. Using Remington cases gives you four colors to choose from. In the 24 gram present, it seems that most shooters use 7 1/2's exclusively, likely because 8's are more difficult to obtain in factory loadings as the American factories—except Fiocchi and RST—supply only 7 1/2s in International loadings. Most shooters use their first barrel at targets at less than 35 yards, a distance at which the patterns are—or at least, can be made—more than adequate with the 24 gram load. High antimony 8's and even 8 1/2's, to sweeten the fringe (and "get a hit"), will work quite well.

Olympic skeet shooters have it easy as there is no problem getting a desired pattern percentage. It's mostly about getting the most uniform, most reliable patterns for them. They too, can use the different colored cases should they feel it worthwhile to have a slightly tighter, higher quality, perhaps slightly higher velocity shell for the longer second shots in station 4 doubles.

It's the second bunker barrel that presents the problem using only 24 grams of 7 1/2 sized shot. The tough decision is whether to use high antimony or "other hardener" shot; the former with higher pellet count, the latter with higher retained energy for greater target-breaking trauma. Either way, with careful shell and choke selection, the pattern can usually be relied upon to break a centered target out to 40 yards. Past that distance, Lady Luck plays a too-large role. Generally, patterns from all but the very best loads fall off at a rate of 12% per 5 yards, making the best 40 yard 24" pattern about 72% and the 45 yard pattern a truly weak-density 60%.

On component choices:

Primers:

It's usually best to match the primer brand to the case brand as they are mechanically designed to work together. However, there are times, as when tuning for best quality patterns when changing primers—if the recipe allows—is worthwhile (changing primers can be dangerous: see Armbrust primer sub tests). See below for more.

Propellants:

Any of the faster powders work very well for 24 gram loads: Red Dot/PROMO, Clays, Clay Dot, E3, HS-700X, Nitro 100, Solo 1000, TiteWad, and American Select. Seems like E3 has a bit of muzzle blast at the >1300'/s velocity levels. Probably Alliant's American Select is the slowest powder that should be considered for top performing 24 gram loads. Your powder choice may well come down to which powder do you have the bushings for or what ever is cheapest at the time of purchase and/or what is reliably stocked. All of the faster burning propellants will do the job very nicely and the patterns will at least be on the the better side. That said and all things considered: after working with the 24 gram load since 1991,when considering cost, availability, housekeeping issues and patterning quality, it would seem that Red Dot/PROMO are the best powders to work with. 

In general, you can expect similar results using Clays, Hi-Skor 700X, Red Dot and other faster burning powders vs. SOLO 1000 and American Select, the slightly slower burn rate powders (Note that you should select the recipes using hotter primers for best pattern performance with the latter two powders). Even slower burning powders as Green Dot, PB and International Clays will provide a harder, longer push with no particular gain in pattern quality and the real possibility of poor patterns when cool primers are used in the recipe.

Wads:

Herein a list of 24 gram-usable wad specifications, including dimensions and weight. All the wads listed perform well, but careful matching of wad to primer/case/powder type is a must for top performance. In testing, I have seen results varying between 73 to 85% in patterning efficiencies at 35 yards with a full choke, depending on how well the components turn out to be matched. I have found the only way to be really sure if the load is good is by actually patterning it. Very often loads that just looked great in the recipe booklets, turned out not so great on the patterning board or on the reloading bench with poor quality, inconsistent crimping. For those who prefer not to pattern, consistently chunky target breaks is a sign of a less than ideal pattern. The better loads will break targets into many, many small pieces, both first and second barrels, although second barrel patterns with 24 grams of shot will produce chunkier breaks.

Do wads make any difference to the pattern?

The tested answer is that wads make a minor—not major—difference. They pretty much are within a small percentage of each other (powder and primer choice has a greater effect), some will be slightly more uniform, others will be slightly tighter and some will have softer recoil—to you—than others. Some are more efficient, needing less powder for the desired velocity.

Good wads to start out with in tapered cases would include the Winchester WW12L, Claybuster 078-12L, the Claybuster CB1100-12 (the latter works very well in the AAHS hull with medium to high-bulk powders). The Federal or Claybuster 12S0 wad works well in the Remington cases.

For straight-wall hulls, as Fiocchi or Cheddite, consider the economical Downrange orange XXL (A word about the XXL. In loading it may be noticed that the top half of the wad cocks occasionally. This does not seem to be a problem as shown by careful pattern testing.), Gualandi REX, and the B&P T2 wad. Ballistic Products colorfully calls the latter: "078Lightning" and Precision Reloading calls it by its B&P number: TUWT2. Reloading data is available from Ballistic Products and Precision Reloading in addition to Hodgdon's web site: www.hodgdon.com. Yes, the wads designed for tapered cases can be used in straight-walled cases, but the small diameter overpowder cups (0.695 - 0.706". See wadlist for more) abetted by static issues can allow powder migration during handling into the cushioning section contributing to more inconsistent load velocities.

Shot:

Probably the biggest concern is sizing and mis-labeling. For tournaments, it is advisable to do a quick sample check with a micrometer to insure the shot is acceptable to you in terms of sizing. Bagged shot sized 7 1/2's (nominally 0.95) seem to have a tolerance range of 0.93 to 0.96 and 8's (nominally 0.90) seem to range 0.87 to 0.91 with the shot much more likely to be on the smaller size. Unless the bag was mis-labeled. It happens. For second barrel work, it's better to use top quality brand name shot of the larger size (0.095 - 0.096) to retain target rim-breaking energy, especially if targets are typically broken much past 40 yards.

Some additional reloading notes:

On recipe selection for the most consistent 24 gram bunker loads:

As a general rule, the 366 in normal operation seems to drop pretty much on the nose. A few drops will be off and finding a +/- 0.3 grains tolerance over a loading session is pretty typical. Looking at the Alliant and Hodgdon loading manuals, many recipes show a full grain difference for 50'/s change in velocity. That suggests that each tenth of a grain roughly equals a 5'/s change in velocity, all other things being equal; pretty linear. Considering the drop tolerance, that translates to +/- 15 '/s from the nominal velocity, again all else being equal. However, there are some recipes that only a half grain difference for a 50'/s velocity change, suggesting each tenth of a grain now equals 10'/s. The +/- 0.3 grain drop tolerance becomes  a +/- 30'/s deviation from the norm, again, all things being equal, double the deviation: the 1300'/s shell now on paper is a 1330'/s - 1270'/s shell that run over a chronograph, will virtually certainly be much worse: not likely a good recipe choice! A few recipes show more than a grain needed for that 50'/s velocity difference and it may be those are the best to start with.  And it's always better to choose basic recipes that show various component options, all at a safe, lower pressure value.

Since a velocity change significantly affects patterns and recoil as well as leads, it seems logical to choose a recipe that shows good linearity. It is also advisable to run 10 shells over a chronograph to insure the load develops consistent velocity and has a low standard deviation. Some recipes that look and load very well will show drop outs: wherein the velocity will be considerably below the average on one or more shells, perhaps on the order of 40 - 50'/s. If your chosen load does this, the only solution is to choose another recipe. Unfortunately, the loading manuals do not indicate the most uniform loads.

Note that when the data is for 7/8 ounce—as is normal in American powder recipe guides, excepting IMR's—and you only load 24 grams, the actual velocity will be around 20 feet per second faster.

Can reloads equal or best factory shell performance? With well-matched components and top quality shot, absolutely!

Some examples with factory runs to compare to:

Reloads:

(Explanatory pattern diagram.)

These pattern runs were done at 35 yards with a fixed, full choke (42.5 thou)
Perazzi barrel. You should note that a slightly more open choke will produce better quality, same percentage patterns. See tite-choke tests. 15 patterns were averaged for the results shown. 

Remington Reload with components as listed above.

AAHS reload: Win209 primer, Alliant PROMO, CB1200-12 high antimony West Coast 7 1/2's.


And for the reference, here are some factory comparison runs:

Factories:

Note the pattern density price paid with the Euro load velocities. This series of tests also demonstrate the advantage lower velocity cartridges offer to hold longer range patterns. If you're shooting targets at 50 yards, this is something you may want to keep in mind.

On initial pellet counts: True, well-graded, 7 1/2's (0.095"/2.41mm) with high antimony will run about 294 pellets in a 24 gram load. The Win AA is only loaded to 23.5 grams, hence the lower pellet count. Lead with "other hardeners" (as, perhaps, tin and nickel) will run about 285 pellets in a 24 gram load. The latter has the advantage of greater downrange pellet energy due to the heavier pellet. A very nice counting block can be found at: www.100straight.com.  

On "90 mm holes": Oberfell and Thompson used a 5" disc to evaluate pattern uniformity. This size was too large: many patterns had no 5" diameter holes (as predicted by O-T), but yet still had significant gaps in coverage. The solution was to use a 90 mm ("midi" target size). The size works out well and gives a more useable way to compare the uniformity of one set of patterns to another. However, early on it was realized that probably at least 25 patterns need to be evaluated for this to become a truly reliable measurement for comparison—unlike the percentage numbers wherein the average changes very little after averaging 10 patterns. Since counting 15 patterns is a very time-consuming process, it was decided to accept that the number shown would only serve as a guide to that load's uniformity.

On adjusting patterns:

Why is this important? Because this will allow taking a few pellets out of a too-hot core and moving them to the mid-taurus. This effort is worthwhile for the first barrel, 24 gram second barrel patterns are never tight enough.

Assuming the recipe you are using will safely allow the change (changing primers can be dangerous: see Armbrust primer sub tests. This article also discusses how changing primers effects patterns), you can move pellets out (or visa-versa) of the 10" core into the 10" to 20" outer taurus (widening the reliable effective pattern) by increasing velocity and/or by choosing a "hotter" primer. If possible, changing the choke tube can also be very helpful as different tubes, though throwing substantially the same pattern percentage, will distribute shot differently. You can see examples of this in here. The H2 figure shows the hole count/uniformity of the 10 to 20" taurus. The lower the figure, the better the pattern, the wider the reliable effective width.

Tweaking patterns is slow, tedious work. The digital camera/computer evaluation method (www.shotgun-insight.com demonstrates one) will speed things up. Usually, the first barrel is adjusted for best uniformity and maximum reliable width (the 24 gram load only has an effective reliable target-breaking width of 20"—at best. The task is to find a choke and load that consistently fills out that circle with virtually no holes. Very, very, very, few loads do; most loads only have a totally reliable effective 12" width.) as well, as getting the desired percentage at the shorter yardage presents little difficulty. If money is not a problem, then test nickel plated shot in the first barrel for tournament-quality shells for highest uniformity/least holes and therefore maximum width. The second barrel is then tweaked for best tightness and uniformity; very high quality, very well graded hard black lead works best.


On Patterning frames and Plates: uses for and how to build.

On the Hornady 366 reloader:

Part I discusses options and 366 set-up with bunker in mind.

Part II discusses tool adjustments/problem solutions for best results.

Part III discusses crimping difficulties and some solutions.

Links:

Please see "Links" on the home page


 
Left arrow points to the 10" core. Right top Arrow points to the 20"-10" taurus
and the right bottom arrow points to the 20" - 24" taurus.

Revised 12/2011