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:

On crimping issues:

On wad insertion issues:

Special section on 410 bore skeet reloading 

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.

Crimping issues:

Tips On making perfect shotshell crimps:

For perfect, flat crimps, the components chosen must have a certain height. The components here come to about 19/32"//12 mm from the top of the shot to the hull mouth for the following crimps. Note the (24 grams of) shot does not overflow the top of the one-ounce Claybuster CB1100-12 wad. Case wall crushing is also eliminated and crimps appear more consistently uniform as a result of this wad choice.




The pre-fold below measures 3/16 across the narrower points. It's better to be a touch on the too much pre-fold side of things than less. However, excessive

pre-fold will lead to a side case mouth bulge giving chambering problems (maximum cartridge diameter is 0.797, per the Lyman Reloading Handbook). Note: if you have an older black-finished final crimp die, the newer 12 (and 20) gauge natural-finished crimp die body dimensions have been changed to improve crimp results. Hornady offers a complete crimper assembly. No number is listed in the parts list, but the nice ladies at the Hornady parts order desk will have it for you.



And this is what things should look like:

Three results showing a nice flat crimp. And no case wall crushing (tire rim around the middle).

Speaking of hull wall crushing (example, right), I'll go with the assumption this is occurring in the final crimp station (it can happen in the Taper-Loc and pre-fold station as well if they are adjusted too low). Be sure the final crimp station is set per the Hornady manual. Note that sometimes increasing the number of threads exposed more than the manual suggests above the locking ring helps. If so, this is a pretty straight-forward fix. The basic problem is simply too much stuff in the case. Other than the "tire rim" around the middle, further proof is usually shown by a convex crimp. Reifenhauser case plastic is relatively weak, so when you adjust for the proper crimp depth when the component length is too much for the case, the result is that the case can buckle, creating the tire rim.

Often, acceptable results can still be achieved by backing off a bit on the final crimp plunger for a slightly shallower crimp. Usually, the easiest long-term solution is to use a shorter wad (A simple alternative could be to jack up the wad pressure to crush the wad shorter. Crimps may not be as consistent.). If you're loading 24 grams, then use the 28 gram wad. Or see the wad list to select a slightly shorter 24 gram wad. An example might going from a Winchester WW12L to Claybuster CB1100-12 to a WW12SL, or from a B&P T2 wad to the Gualandi REX or even the SPARX, depending on the case type.

Other possibilities include going to a higher-capacity hull with deeper basewad, or with an 8 fold crimp instead of 6 fold or using a denser powder, as switching from Red Dot/Clays recipes to those offered for HiSkor-700X, Nitro 100 or a ball powder type as TiteWad.

This is a minimal amount of pre-fold in this B&P case. In general, for most plastics, this small amount won't work with an unacceptable crimp resulting, but it varies depending on case plastic type and construction (see next section). It's safest to go with the 1/4" prefold as a standard. A bit less pre-fold than the standard 1/4" is useful with the longer component combinations to achieve a flat crimp, but there is little room for error: defective crimps tend to start showing up in a hurry.


Note flatness, but hole in center of crimp, left two shells because of too little pre-fold. (Center shell is the shell shown above.) Perfect crimp on the right hand shell after final pre-fold increase tweak. It's sensitive at this point: adjust a quarter turn at a time. Also with insufficient pre-fold, you can experience significant operating handle resistance as the crimp plunger hits the top of the case mouth, crushing same until the plastic folds over. In addition to the high resistance until the plastic folds, the crimps have a unique look:

Left, example result of crushing the case mouth in the crimping station. Right, how the crimp should look with proper pre-fold. Note clean, sharp center.

A caution on setting Reifenhauser pre-fold:

Using pre-fold to the point where the crimp line bulges out sometimes results in the above - type case indentations. These sometimes are bad enough to cause chambering difficulties. The older Scot Powder Solo1000 powder manual (eighth edition) had a picture like this with the admonition not to shoot them. No further explanation was offered. . .

Examples of excess prefold, left and right. Perfect prefold, center. Notice the smooth hull line.

Often with Reifenhauser type cases, it will seem that you can't quite get enough pre-fold without bulging out the sides of the case mouth at the crimp line. For example, when you're trying to close a hole in the crimp's center. At this point, try this: set the pre-fold to just before the point where the case mouth bulges, and on the final crimp die, back off the crimp plunger several turns and lower the die body down so that the radii of the final crimp die can act as a final prefold. Adjusted correctly, the crimp die can close the prefold gap enough to solve the problem. Then just lower the crimp plunger to the desired crimp depth. Be aware that lowering the die body too much can result in case side crushing with some hull plastics, as with the AAHS cases..

On another note, if you start observing off-center/bad crimps, remove and check the prefold die. The latest incarnation of this die uses high, thin ridges. While this definitely improves crimp quality over the old triangular shape, mechanically the ridges are weaker; they can and do break. As you can see below:

Yep , they DO break. Note the broken ridges to the left and right.

Note both crimps are off center with one or more badly formed sections. One or two could be a fluke; several, time to check the pre-fold die for damage.

Does case length matter?

Results of pre-fold set for 70 mm hulls, then 68 mm hulls loaded:

366 set for Remington STS 70 mm hulls. Left, 70 mm hull prefold 1/4"//6.3mm. Right hull 68 mm, or 3/32"//2 mm shorter. Note the prefold width is considerably wider. And the crimping results? See below:

The 70 mm length STS hulls with the 1/4" prefold diameter crimps perfectly. Three shells of 68 mm length in the middle crimped poorly with the inadequate prefold. Many hulls will crimp good enough, but too many will crimp as above. The right two hulls shown resulted after after increasing the prefold to 1/4" diameter: perfect, flat, crimps.

One more example of what happens when the 366 is set, in this case for 68 mm hulls, and hulls shorter or longer slip in. Left hulls are 66 mm in length. Note the center hole: close inspection will show no bb's as they've already fallen out. Center, 68 mm length hulls -- the majority of the lot available -- with perfect crimps as the 366 was set for this length hull. Right, the convexity resulting from slightly longer hulls. As you can see, varying hull plastics deliver different consequences when length is not identical to the original pre-fold setting. It's best to set up the prefold die for the shorter cases you will load. When a longer case is loaded, you will probably see some convexity and other not-so-great crimps, but it's better than having bb's falling out as above. Of course, ideally, each hull would be the same length, eliminating this issue. Unfortunately for reloaders, manufacturers need a flexible tolerance in making shells.

Consequences of a mal-formed prefold:

Shell that came out of the pre-fold die in disaster shape

And if you proceed to final crimp, here are what the results typically look like.

Another example of results from an improper pre-fold. Note the BB's ready to slip out and float around your shooting vest pocket.



Left: An example of a hull likely to badly pre-fold. Note the nearly non-existent crimp lines on the right side of the hull. Often a potential bad pre-fold occurs with empties that come from factory shells that were loaded to high velocities, as the 1300'/s 1 1/8 oz (32 gram) Sporting Clays loads by Remington and Winchester. The handicaps are also somewhat liable. If this problem is spotted before running through the 366, a quick hit (right photo) with a spare prefold die by hand can insure a good crimp. Doesn't seem to take much to help as you can see. The MEC brass new-case crimp starter seems to work a bit better than the standard Hornady plastic pre-fold die. Considering how often this problem comes up with hulls from the high velocity factory shells, it's worth inspecting the hulls before loading and using the spare prefold die as needed to insure good crimps.

Interestingly, the problem never seems to appear with the Winchester or Remington factory 1325'/s 24 gram bunker loads, only with the 1 1/8 oz (32 gram) 1300'/s high velocity loads.

More on wad insertion issues:

Arrow points to the just barely visible nick in the case mouth caused by the wad's OP cup catching. Note the consequence to the wad. This was caught because of the operating handle resistance and an insertion sound that was just a tad not quite right. Doubtful this would normally be caught visually. Hull was likely tilted in the station, causing the wad guide fingers to mis-insert. If you have occasional, unexpected pookies, this may be one explanation.

Example of hulls that may cause wad insertion problems. These were picked up off a field and were obviously somebody's bad-crimp rejects. Curiously, once a hull has crimped bad, it seems much harder to fix and rather than waste a lot of time attempting to fix the crimp before loading, it's better to leave them lay.




Maybe another reason not to pick up hulls: AAHS hulls will warp-distort if left exposed to bake in summer's hot sun. For one, hulls in this condition may well catch a wad's overpowder cup rim in the wad insertion station.

Hornady 366 Special Section:

Reloading 410 bore NSSA skeet shotshells.

Reloading 410: does it make sense? New, highly reloadable, Winchester or Remington 410 shells cost around $90 – $110 per case of 250. Reloading those cases costs in the neighborhood of $35 - $40 a case. Quite a savings. If you do any significant amount of 410 skeet (or sporting clay) shooting, it makes economic sense to reload them.

Hornady does not offer a die kit to load 410 making the easiest way to get a Hornady 366 for 410 reloading is to buy a new or used one (and then buy the die kits as needed for 28, 20 and 12 gauge). As mentioned, while for whatever their reasons, Hornady does not sell a 410 die kit, it would seem possible to "part out" and acquire the dies that way if it comes to that, provided you feel comfortable and experienced enough with the 366. See Hornady's master parts list in the back pages of the Hornady 366 manual. (PDF file).

Hulls:

For hulls, the Winchester 410 seems to last the longest. . . Although the Remingtons, in a reversal of the 12 and 20 gauge experience, resize easier. As a factory shell, the Winchester also has the virtue of excellent consistency over the chronograph in the lots I've tested. 410 (and 28 ga) hulls tend to be hard to come by: they are rarely seen laying on the grounds. As always, the best way is to buy new factories, fire them in your gun, and reload them.

Powder issues:

There are 7 (8? Alliant now lists 410 bore data for their 300-MP) powders usable for 410 reloading: Accurate's 4100, Alliant's 410 and 2400, Hodgdon's Lil' Gun and H110, IMR's 7225 and Winchester's 296. Good Old Timers Alliant (nee Hercules) 2400 and IMR 7225 (nee Dupont) are not often used with today's all plastic components because of pressure or bulking issues. They worked quite well with the nitro card/"felt" wad columns of yesteryear—especially 2400 in the paper cases of the time—and now work with only some very few current plastic component sets, judging by the few available manufacturer's recipes.  

So for all the usual reasons (availability, bushings, etc.) it essentially comes down to these four: Alliant's 410, Hodgdon's Lil' Gun and H110, plus Winchester's 296. These four could be boiled down further by your desired velocities. If you want your shells to be 1250—1300 '/s, then you'll be using the more elastic H110 or 296 (these powders also certainly quite work well at 1200'/s, just not as economical compared to the following two). While Alliant's 410 and Hodgdon's Lil' Gun excel at the 1200'/s level; the manufacturer's data sheets show that pressures run too hot (are unsafe) at higher velocities. Alliant's 410 is the most economical to use (nearly 19 10-box cases can be loaded from a single 8# keg) and has the cleanest burn, with very little ash left in the barrel. Both of these latter propellants are also pretty free of powder leakage housekeeping issues at the loading bench.

296 and H110 are very fine-grained ball powders. If you find these grains around the 366 where you don't want them, try taking a business card and cutting out a washer to slip under the rubber powder measure seal. This usually solves the problem. The problem's first clue often will be seeing powder grains atop the charge bar when the handle is topmost. Powder leakage can build up creating powder/shot shut-off jamming. The worst case is charge bar jamming causing erratic drops. You may have to remove the measure plate to insure the assembly is completely clean.

Another source of H110/296 powder leakage is where the powder tube is attached to the measure casting. An electrical-tape seal is a quick solution. The after-market powder and shot tubes also solve this housekeeping problem neatly without the need for tape and add considerable reservoir capacity as well. www.basicdesignmachine.com and Jim Skeel: **xskeeljc@verizon.net**x are two sources of after market tubes (remove the **x for Jim Skeel's email address). Neither Alliant 410 nor Hodgdon Lil' gun propellants will have these specific problems.

The Powder Bushings issue:

Powder bushings: This is one time that maybe it's wise to learn which 410 powder is in most reliable inventory at your local sources and stick with it. Hornady offers only five bushings for 410 powders. Unlike for bunker powders, there are gaps between the bushing offerings, but the drops will be pretty close to recipe specs. If you want to zero in on the exact drops required, there are several routes available: tape or build up the walls of a larger bushing with nail polish or the like, buy the bushings that Ponsness-Warren offers: 1A, 2A, 3A and 1AX, 2AX, 3AX. Or buy the MEC to Hornady bushing adapter available from Precision Reloading/Ballistic Products, among others and buy/use MEC bushings. Since the machine vibration will likely be different, you may want to buy more than just the one bushing specifically suggesting the desired drop from the MEC chart. Changing to a different manufacturer's bushings sometimes works because of that difference in machine vibration. For example, the Ponsness-Warren 2A bushing appears to drop about three-tenths of a grain more Winchester 296 powder than Hornady's #266 bushing: that may hit the exact recommended recipe drop specified in the recipe you're using, avoiding the need to ream or file out a Hornady #266 bushing to get the exact value.

You may still have to ream out one of the above to get exactly the recipe-specified powder drop and hope the next powder lot drops the same amount. If you do this, be sure to mark the bushing clearly and appropriately so you can come back to it the next session if you need it. Perhaps obviously, an accurate powder weight scale is an absolute necessity to get and confirm the powder manufacturer's recipe-specified drops are right for safe, quality, 410 reloading. Quite candidly, do not load without using one to check that your powder drops are to the factory recipe's specifications.

Wads:

All of the major wad suppliers offer one. And that's it. One. Each. Unlike the sometimes bewildering multiple offerings available for 12 gauge reloading from a single manufacturer, as Claybuster or Downrange. Occasionally it seems that cases have a different volume after multiple reloadings, so keeping a couple of wad flavors that still work with your basic recipe might be worthwhile if you run into this.

American 410 wads are really pretty similar (see 410 wad measurements): they have only an OP and shot cup; there is no cushioning section. Probably some will pattern and/or chronograph better, but the only way to know is to do the work with your barrels. The wad choice may come down to what is most reliably in inventory at your sources and that reloading recipes exist for.

Left: shot too high—almost to the rim—in the case. Too much shot or powder? Nope—see the right picture: it's due to the wad petals not lying against the shell walls, reducing the shot chamber capacity, usually because a shot pellet(s) lands perfectly to hold the petal(s) away from the case wall. Happens in 12 ga too, but the problem is more critical in the pee-wee 410 cases.

Examples of defective wad petal shapes that can create the "excess shot" problem shown above, left and center. Right, perfect petal alignment. Petals can be bent back into alignment. Seems like all brands can have this problem.

Shot selection:

Considering that the cheaper soft shot deforms so easily—delivering more open patterns, perhaps desirable in the 12, but something not so desirable in the 1/2 ounce 410 skeet load—the only real choice for 410 reloading is high antimony magnum shot from such suppliers as Remington, West Coast, et al. Not only will the patterns be at their best, but the antimony hardener makes each pellet lighter putting extra pellets in each pattern.

For tournament loadings, this is probably one of those times where it's worthwhile to mike, or at least carefully inspect, shot size. Interestingly, in general, it seems that when the shot label says 7 1/2, or an expected true 0.095 average diameter, the average size tends to be smaller. With 8's the shot average size is almost always smaller. 8 1/2's are random. 9's tend to be larger than the true average size of 0.80". For latter example, the last lots of shot checked showed that the "8 1/2's" were noticibly smaller than the "9's". Both measured larger than the true size 9. Double-checking shot size will give you confidence that your shells are the best for you, creating that extra tournament-winning confidence.

Shot bushings:

Hornady offers two half-ounce shot bushings. One for target, one for field loads with larger sized shot (Be aware that shot larger than size 8 1/2 can jam together in the 410 (and 28) shot drop tube. Visually checking the shot level in the case before advancing each shell to the pre-fold station is a wise precaution and a strongly recommended loading procedure/habit to have in this situation.). The shot field bushing drops a bit more than 218 grains, 1/2 ounce shot drop with high-antimony #9 shot—about 227 grains. The #9 skeet bushing drops about 220 grains with high-antimony #9 shot. Drops about 222 grains with shot using "other hardeners". Probably drops about 225 grains with chilled soft-lead shot.

Depending on the shot quality, sizing and grading, you may want to use the field bushing to allow control of the shot drop with different flavors of lead by taping the bushing. The NSSA shot loading tolerance is a generous maximum of 14 grains (232 grains: about 20 #9 high antimony pellets more than the specified 1/2 oz 218 grains, which has a pellet count of around 320 pellets—27 pellets more than is in a proper 24 gram bunker load of 7 1/2's. Interestingly, the ISSF bunker/ISkt shell loading tolerance is noticibly tighter: 8 grains.); the field bushings seem to be closer to that with high-antimony 9 shot—but not over—so the cartridge control police likely won't get you if you shoot a tournament and this is your only bushing. If your bushing drops less than 226 grains using high-antimony #9s, it will likely handle normal drop variations and keep the occasional shell from getting the cartridge control police excited (and you know which ones they are going to pull out of your shell pouch!).

Crimping Issues:

To start with, what they should look like using AAHS hulls: Left, perfect prefold and right, the result.

A few more examples of expectable (AAHS) crimps. Bottom left and center: Winchester AAHS factory shells. Top left and center, two perfect crimps. Upper right, flat to slightly convex crimp from insufficient prefold caused by a short case that was fixed with additional hand-applied prefold using a spare crimp die. Final crimper is set too short for the shorter case (Note the lack of crimp depth.). Lower right, a not un-typical crimp just about closed enough to keep the #9 shot in.

Left: Insufficient prefold. Needs to be folded down to about a 3 mm gap for reliable results. Insufficient prefold usually occurs when a shorter case is used than the prefold die is set for—as you would expect, 410 cases are no exception to the pre-fold set-for-length  rule. Center and right, the result. The difference in case length is about 1 mm shorter—doesn't take much. Winchester HS 410 cases seem to vary about 0.04"/1 mm (63 mm +/- 1mm), enough to create the above problem unless sorted by length. Federal cases seem about 2.44"/62 mm, Cheddite 2.48"/63 mm and based on past 12 ga experience, plus actual Cheddite 410 case measurements, there will be virtually no length variance. Remington case length is about 2.52"/64 mm.

Remington crimp results with the 366. The two left shells are factories for reference.

It is possible to close the crimp a bit more to eliminate the center holes, but the price can be a bulge out at the crimp line that increases chambering difficulties (maximum cartridge dimension is 0.462, per the 5th Edition Lyman Reloading Handbook, page 408). The result then may be that shells will then need to be pushed into the chamber rather than them just going in easily. An inconvenience in over-unders, could be a jam in pumps or autoloaders. It's best to set the pre-fold to the point just before the case starts to show a side bulge (the case line is still smooth). then use the least amount of crimp depth possible to assure chambering ease and longer case life.

It may just be an function of the older 366 410 final crimp dies, but for best crimps, try—unlike with the 12 and 20 final crimp die settings—threading the crimp plunger all the way to the top of the die body and adjust only the final crimp die bushing body for the desired crimp depth. This setting works for both Remington and Winchester cases; the 366, with perhaps a very minor initial tweak or two, loads both cases identically. Note: the powder charges are different for each case and will require different bushings.

A 28 Ga Note:

Many of the above comments apply to 28 ga as well. Both require more time consuming attention to the process. For that reason—just like the big factory loader's experience where 10,000+ shells per hour production rate is often the norm in 12 ga, but 410 runs are about 2400 per hour—you may get a much slower production rate, perhaps as low as 150+ per hour as compared to the typical 400 shells per hour average comfortably achievable in 12 ga. However, the actual rate can easily be at the 400/hour rate: case mouth hull condition and wad petal alignment are the big factors in 410 reloading speed as well as your level of desired crimp perfection. Once-fired Remington's seem to be the fastest loading, easily matching the 400/hour (if oops free!) rate of 12 gauge.

End part III, 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 back 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!

Last revision: 3/2012