Lousy & Illogical statistics but GREAT 5-shot pistol groups. Go figure . . .

[JimGnitecki]

Then with the excluded groups you knew the moment a shot broke that it was bad because the sights were misaligned, correct?

Or was your approach: this group is big I must have screwed up?

Combination. If you think about it, you will see why:

If the group is larger because I screwed up, it does not tell us anything useful about that variant of the ammunition being tested.

If the group is larger purely because of that variant of the ammunition, then we don't need to further analyze that variant of the ammunition because its inferior group size compared to others tells us it is clearly not the best variant to test and pursue further. (Since targets with other variants already have better groups)

Sometimes, it IS hard to figure out which (me or the ammo) caused the larger group, but there are some clues that help, including some I got within the past few days from Michael Ransom at Ransom Rests via literally MANY pages of text on how to "do it right" and to how to KNOW when you are doing it right.

What Michael told me, maybe somewhat simplified, basically boils down to: IF it is purely a combination of decent ammunition, decent firearm, and decent firing point stability that has shot a Ransom Rest group, the distribution of the individual holes in the target should be fairly evenly spread around an axis. i.e. A true random dispersion with no centerpoint deviation or non-symmetric shapes.

If the overall shape or concentration of holes differs from that, you have one or multiple uncontrolled ammunition, firearm, or user variables.

That leaves a LOT of potential variables to identify and analyze!

No, I am NOT using a Ransom Rest as the Canadian cost for a fully equipped rest with recommended accessories is over $1000 plus the costs and time of COVID era shipping, plus 12% Canadian sales tax and any duties, and still requires range benches with very specific standards of stability AND stiffness that would surprise most people.

Michael says that I can get pretty consistent results IF I build a proper LARGE and thick wooden base myself to fasten the Ransom Rest to (versus his 30 lb solid steel plate offering), and then clamp that setup to the shooting bench with at least 3 clamps on at least 2 sides, and iF the outdoor range's shooting benches are stiff enough without needing to be reinforced with tension straps to nearby objects (no kidding), but the cost would still be north of $750 Canadian plus shipping and taxes.

It would also not have any provisions for windage changes without stepping downrange instead to change targets manually after each group, which is difficult to do when many other shooters are using the range at the same time and you irritate them with multiple calls for cease fires. Those Youtube videos you can see where the user has simply clamped the Ransom Rest by itself to a shooting table and Tested his firearm and/or ammunition without any further provisions have NOT really tested his firearm and/or ammunition.

Jim G

 

[fxvr5]

Combination. If you think about it, you will see why:

If the group is larger because I screwed up, it does not tell us anything useful about that variant of the ammunition being tested.

If the group is larger purely because of that variant of the ammunition, then we don't need to further analyze that variant of the ammunition because its inferior group size compared to others tells us it is clearly not the best variant to test and pursue further. (Since targets with other variants already have better groups)

Sometimes, it IS hard to figure out which (me or the ammo) caused the larger group, but there are some clues that help, including some I got within the past few days from Michael Ransom at Ransom Rests via literally MANY pages of text on how to "do it right" and to how to KNOW when you are doing it right.

What Michael told me, maybe somewhat simplified, basically boils down to: IF it is purely a combination of decent ammunition, decent firearm, and decent firing point stability that has shot a Ransom Rest group, the distribution of the individual holes in the target should be fairly evenly spread around an axis. i.e. A true random dispersion with no centerpoint deviation or non-symmetric shapes.

If the overall shape or concentration of holes differs from that, you have one or multiple uncontrolled ammunition, firearm, or user variables.

That leaves a LOT of potential variables to identify and analyze!

Mr Ransom's comments are based on a theoretical distribution with MANY assumptions. It fails to take into account that random probability will produce groups that are not consistent with his assumptions. Therefore, it's not of great value when looking at actual data.

Additionally, Jim, you're not indexing a center point so you have no information on how your shots deviate from it and whether your groups are symmetric shapes or not. If you were indexing a center point, you'd already have that information in the first run of your analysis.

I shoot from a Ransom Rest and I get lots of non-symmetric shapes.

How many of your groups had shots that you knew had fliers that you could specifically position their hits in relation to the other hits? That is, they were called fliers and you knew where they were going to be in your 'group'? How many were called fliers? If you can't account for those, you're throwing out data that reveals the REAL accuracy of your ammo, and only accepting groups that fit some 'ideal' group in your imagination. The REAL accuracy of your ammo might be a 5" group at 25 yards, not the imaginary small size you want it to be.

Imagine if everyone did that. We could pick any bullet/powder combination we want and eventually produce a group small enough to make it "the most accurate ammo in the world".

You're guilty of sampling bias - only picking the groups of which you approve - the smallest groups. This error is explained that this link: https://www.ssusa.org/articles/2019/9/25/accuracy-testing-shortcomings-of-the-five-shot-group/

You say you've read that article but you don't seem to understand the full implications of it.

 

[JimGnitecki]

fxvr5: I am using techniques that I have used for decades of load development for many different firearms. They have worked for me. The "large scale and keep and analyze ALL targets" approach you seem to be advocating might be doable and even might be appropriate for a large ammunition company looking to develop and refine a cartridge load who also has a full and properly set up Ransom Rest or equivalent environment, and who wants to certify its statistical accuracy to say for example the U.S. Military But it is wildly impractical, unaffordable, and unnecessary for someone developing a load to work in his or her personal firearm.

I am not going to make, measure, fire off, and analyze hundreds or thousands of rounds to find a good load for my personal handgun, when I know from many years of experience that I can get to a suitable load by firing dozens, not hundreds of rounds. I am not trying to create ammunition that will 100% of the time produce groups of a specific size or smaller. It would be a giant waste to even try since I do not have EITHER that perfected Ransom setup to fire, record, and analyze hundreds of statistically perfect rounds, nor the personal capabilities (especially eyesight) required to do it without a Ransom rest (or other similar equipment if it exists). So, I would never try to claim that any handload I do settle on will consistently shoot "x" size group or smaller.

But I can safely say right now that I have never before managed to shoot 5-shot groups under 1" in diameter at 25 yards. So, regardless of what any statistical analysis on this too small a sample might show, I know that I have hit a new personal best.

Furthermore, since I don't see any magazine or Internet gun tests that show anyone achieving sub 1" groups from any semiauto pistol with EVERY target string they fire, I have no reason to think that it is even possible to do so. I'd love it if I could, but I will not consider my efforts a failure if I cannot.

I am seeing useful patterns and progress in what I am doing, and will continue.

Jim G

 

[JimGnitecki]

Someone (not in this thread) has suggested to me that there may be a different explanation than I theorized for the lack of significant difference between the COAL to Tip and the base to .338 Gage standard deviation calculations I did.

He said that he realizes that the Redding seating die is intended to grab the ogive versus the tip of the bullet, and that the hole in the top end of the narrowing cone in the die is larger than the bullet tip diameter, so the bullet tip should be able to go right through the hole and then the ogive can be stopped and seated by the narrowing cone. But, he speculated, what if the hole is not quite large enough to let a slightly tilted bullet tip pass, and instead the bullet tip catches the edge of the narrowing cone?

This is a worthy speculation to address, since the pass-through hole is not that much larger than the diameter of the HAP bullet tips.

It is particularly likely in fact because the entry to the narrowing cone in the die is at least .381" in diameter, in order to accommodate flared cases, and even just the extra diameter of the case (.3750") versus the bullet (.3548").

My cases are well under that diameter after sizing and very minimal belling as explained in my first or second posting in this thread.

So, the bullets can indeed be slightly tilted as they slide upward through the narrowing cone in the die. And if they are tilted, they CAN catch the edge of the passthrough hole. If a tip does catch the edge of the cone, it can be pushed downward a bit into the case before the ogive gets stopped by the narrowing cone.

What I am CONSIDERING is drilling out the hole to a larger size. This would enable the bullet tip to pass through reliably even if slightly tilted, and the narrowing cone would still catch the ogive, which has a much larger diameter than the tip, even just a short distance below the tip.

Anyone see any potential problems with this idea?

I WOULD have to be careful to drill that hole "on-center" and with the drill bit axially aligned with the narrowing cone or darn close, because I don't know, and cannot see, how far up the narrowing cone the ogive travels before getting stopped by the narrowing cone. I wonder if I could determine that by painting the inside of the narrowing cone with a washable marker and running a cartridge up into it, and then look for the marker paint on the bullet's ogive.

Jim G

 

[fxvr5]

And you still don't get it.

 

[forrest r]

Have you used 3N38 in a 9mm? Have you ever used 3N38?

I have no idea why you think I would bother wasting my $$$ on that powder. If I want a 115gr bullet to go 1300fps+ in a 9mm I'll use power pistol and my 3.2" compact 9mm pistol.

 

[forrest r]

There's a thing called dwell time, it affects bullet dispersion. Most shooters can't hold a firearm still/steady when shooting and the firearm ends up moving. The longer the bullet stays in the bbl the more it's affected by this movement. Typical movement is from recoil hence vertical stringing. Simply put. You hit the loud button, the pistol moves upward from recoil. The longer the bullet stay in the bbl (slower bullet) the more the upward movement. higher shot. Dwell time All the ballistics calculators in the world don't take this into account.

The short start pressure is exactly what you want to use to try to increase the % of burn rate or more importantly. Decrease the extremes of the velocity spreads. Slower powders tend to do better with a solid/heavy crimp. The length of the crimp will have more affect on over pressure then the +/- 2/1000th's difference in the crimp depth. Some reloading dies have a llloooonnnnnggggg taper crimp to them. Myself I like to use the cheap lee taper crimp dies. A 3/1000th's " taper crimp is +/- .035" long and leaves a ring mark in pulled bullets. That ring doesn't break the 2/1000th's" coating of pc'd bullets. Nor does it egg/make the bullets out of round.

Neck tension plays a roll in the short start pressure/consistent burn of a load. Myself I prefer a long bodied bullet and the correct expander for that long bodied bullet.

 

[forrest r]

I'm glad you did your research and came up with what you consider a winning combo. Myself, I see it as nothing more then parroting generalizations that companies like hornady have come up with for a 1 size fits all solution.

What your using is good enough for the major power/steel games. Big difference between raw accuracy and accurate enough to play games with.

 

[fxvr5]

I have no idea why you think I would bother wasting my $$$ on that powder. If I want a 115gr bullet to go 1300fps+ in a 9mm I'll use power pistol and my 3.2" compact 9mm pistol.

In your previous post you said that 3N38 does better with heavier bullets. Yet you have no experience with this powder. Hmmm.

 

[forrest r]

In your previous post you said that 3N38 does better with heavier bullets. Yet you have no experience with this powder. Hmmm.

Perhaps it might be because I have several friends that have burned #'s of the stuff in their 9mm's & 40cal's.
Perhaps it might be because I have several friends that have burned #'s of the stuff in their 9mm's & 40cal's using different bullet designs, styles, weight.

Just because I haven't waisted my $$$ on a powder doesn't mean I haven't seen what it's capable of 1st hand. Or talked to people that have used it along with shooting their firearm/reload combo's.

I stand by my statement, 8N38 does better with heavier bullets. In that context the op is using a 115gr bullet in a 9mm. I'm saying that that 8N38 powder would do better with a 124gr or 135gr bullet.

And just so you're not confused:
Better ='s more consistent velocities with smaller es's.

100fps+ difference in loads is 1 thing. 100fps+ in a small capacity case like a 9mm using a powder that +/- 95% fill is called a clue.

 

[forrest r]

OP,
I'm not telling you to change bbl's. The p210 bbl's chamber is cut similar to the old bar-sto target bbl's.

Perhaps if you spent less time reading/parroting what others are using/doing & more time actually learning what you have. You could make better choices in bullet designs to set a benchmark to compare other loads to accuracy wise.

Is your bbl throated??? "Gee I don't know but I bought these here bullets because they said so". My dog is right there when he hears anything wrapped in plastic make noise (things like potato chip bags). "Gee, it's wrapped in plastic so it's gotta be good!!!!".

A picture of an un-throated bbl shipped this way from the factory


Same bbl after a throating reamer was used on it


You bbl should have a 3* tapered forcing cone which makes the angle on the lands 3*. This makes for a long taper on the lands that not only cradle the bullet. It aids in alignment of the bullet to the bore.

This is a rifle chamber with a 1 1/2* angle.


3 different pictures showing the length of the angle cuts on the lands.

What you have done with your careful reading/studying and asking your experts for advice is selected a bullet that has a bullet nose that will give you a 1 point alignment.

1 point alignment ='s
The angle of the bullets nose you selected is so extreme compared to the angle in your bbl's throat/leade that the 2 angles will meet only at 1 sharp point for alignment to the bore. If your bullet is not seated perfectly strait it will engrave more on 1 side then the other with the bore alignment. Anything under pressure will go to the point of least resistance. Hence that bullet will move sideways as it move forward. This will also affect your short start pressure/powder burn/es's.

1 bullet is strait which means an even launch to the bore and an even short start pressure the whole way around the case. A crooked bullet has to re-align as it enters the bore putting more pressure on 1 side the case giving the short start pressure a place to go/escape changing the burn of the powder which it turn changes the velocity of the loads.

There's nothing wrong with 3n38 and that 115gr hap bullet for IPSC and USPSA. Shooting bugholes on the other hand, not so much.

 

[lordpaxman]

But, it bothers me. That magnitude of variation in velocity should not be occurring. What am I doing wrong?

What you are doing wrong is not adding a lot of columns to that worksheet including powder type, lot and weight to the nearest hundredth, primer type and lot, neck tension etc. Then you’ll scratch your head even more when a larger charge weight and smaller COL result in a lower velocity than a corresponding higher charge weight and longer COL. You can chase these across several powders and primer types, oh, and lots. Please don’t ask how I know.
Then you can go back to the group size and see for pistol and shorter ranges holes on paper is all you really need, unless you need to meet a PF.
I applaud your level of attention to detail. If it makes you happy, that’s a bonus. I also like the VV powders but have never tried 3N38. For some reason I didn’t think the P210 had a compensator. I’ve got a lot of sigs in the stable but not a 210. Good luck!

 

[JimGnitecki]

Forrestr: I appreciate your taking the time to educate me on the significance of the 3 degree reaming process for a barrel, and how it affects bullet engagement. I had never before been made aware of this.

But I am not going to modify my barrel in any way, as a P210A shoots better than most handguns as it comes from the factory.

I am also not going to change bullets. Our bullet choices in Canada are much more limited than in The U.S. Bullets are heavy and our shipping distances are hugely longer than in The U.S. (e.g. When I lived in Austin, Texas I was only about 1450 miles from my relatives in Ontario, Canada. Now that I am on the west coast of CANADA, I am 2600 miles from those relatives). So, since bullets are heavy, and shipping distance are long, bullets tend to be quite expensive in Canada, and our Canadian reloading supply houses don't carry a lot of "choices", especially choices that have to cross the border, and choices that are costly even before the shipping costs. For 115g 9mm bullets, the Hornady 115g HAPs are the only quality choice. All the other bullets available to me are a big step down in quality.

I did some measurements last evening on the HAP bullets and the Redding seating die insert. I found that while diameter of an ink imprint of the tip of the bullet is smaller than the tip passthrough hole in the die insert, the transition zone from that tip into the ogive makes the digital caliper measured diameter large enough to indeed snag the edges of the passthrough hole. So, the bullets are NOT being seated via contact with the truncated cone ogive, but rather by that very narrow transition zone, which seems like a prescription for notable and variable error.

My buddy up here who does a lot of 900 and 1000 yard rifle shooting says that I should consider modifying the seating insert to match the needs of the bullet shape I am actually using. At least in theory, I could enlarge the passthrough hole so that its edges cannot catch the bullet tip, and lap the narrowing cone section of the seating die insert below the passthrough hole with lapping compound to exactly conform to the shape of the bullet ogive.

A precise enough enlargement of the passthrough hole could be achieved by mounting the insert in a lathe and drilling it out to a larger diameter.

A precise customization of the narrowing cone section below the passthrough hole could be achieved by then running one bullet after another, each coated with lapping compound, and being rotated at a slow speed, into the die insert until the narrowing cone in the insert has been ground down to exactly match the bullet ogive. My buddy says that when he does this, the bullets you use one after another of course each "wear" until the metal jacket is gone and you then just change to a fresh bullet. Repeat until the shape inside the die exactly matches the bullet ogive shape.

Having done that, any bullet entering the die has no choice but to be seated by the ogive versus tip. Also, the contact area between the bullet ogive and die insert will be much larger than a mere "line" of contact, improving accuracy and consistency of the seating depth.

I don't have a lathe, but I suspect I could find a local machine shop that could do this.

Thoughts?

Jim G

 

[Jim Watson]

If the group is larger purely because of that variant of the ammunition, then we don't need to further analyze that variant of the ammunition because its inferior group size compared to others tells us it is clearly not the best variant to test and pursue further. (Since targets with other variants already have better groups)

Not really. As Bart B., rifle shooter says, it is not your smallest groups that govern, it is your largest groups that matter because that is all you can count on. Small is not small unless it is repeatably small. And you are not shooting a lot of replicates with any one load. One or a few small groups may well be chance, the big ones just didn't show up that time.

Called shots. Just cherry picking the four closest hits out of five is not enough. You are already doing very well for any form of handheld shooting.
If you can fire a shot, call it either good or call it off center and in what direction, then spot that individual shot and whether it went to call or not, you have a chance at reducing human error vs mechanical error. But you have to call and mark each individual shot. If you call one left and it went up, you lose, that one has to count.

Ransom Rests. My club's old range had a concrete pedestal for a Ransom Rest, and we shot some good targets from it. But my gunsmith was still doubtful of the rubber inserts. So we shot some by laying the gun individually for each shot with a scope sight in V blocks on top of the slide. Groups were even smaller.

Seating dies. The latest issue of Blue Press has a puff piece on how a Dillon seating die gave slightly but noticeably more uniform OAL than a Redding like yours. What he didn't mention was the difficulty of adjusting the Dillon die to a desired OAL by turning the whole die in its coarse body threads and the even greater difficulty in going back to a previously used OAL.

I see no reason not to modify your seating stem to suit your preferred bullet. I don't know if they will sell you a replacement if you ruin it; they do offer standard stems but I don't see the micrometer type stem only.

 

[JimGnitecki]

Not really. As Bart B., rifle shooter says, it is not your smallest groups that govern, it is your largest groups that matter because that is all you can count on. Small is not small unless it is repeatably small. And you are not shooting a lot of replicates with any one load. One or a few small groups may well be chance, the big ones just didn't show up that time.

Called shots. Just cherry picking the four closest hits out of five is not enough. You are already doing very well for any form of handheld shooting.
If you can fire a shot, call it either good or call it off center and in what direction, then spot that individual shot and whether it went to call or not, you have a chance at reducing human error vs mechanical error. But you have to call and mark each individual shot. If you call one left and it went up, you lose, that one has to count.

Ransom Rests. My club's old range had a concrete pedestal for a Ransom Rest, and we shot some good targets from it. But my gunsmith was still doubtful of the rubber inserts. So we shot some by laying the gun individually for each shot with a scope sight in V blocks on top of the slide. Groups were even smaller.

Seating dies. The latest issue of Blue Press has a puff piece on how a Dillon seating die gave slightly but noticeably more uniform OAL than a Redding like yours. What he didn't mention was the difficulty of adjusting the Dillon die to a desired OAL by turning the whole die in its coarse body threads and the even greater difficulty in going back to a previously used OAL.

I see no reason not to modify your seating stem to suit your preferred bullet. I don't know if they will sell you a replacement if you ruin it; they do offer standard stems but I don't see the micrometer type stem only.

Jim Watson, you have me thinking about some of the things you said, especially the comment about "we shot some by laying the gun individually for each shot with a scope sight in V blocks on top of the slide. Groups were even smaller." !!

Yes, adjusting the Dillon seating die to any SPECIFIC OAL is slow and iterative. Plus, you create a lot of variable length ammo doing it because you are trying to avoid running the press with some stations unoccupied, which screws up the OAL you adjust to once you start filling the stations. That's one of the reasons I got the Redding die with its micrometer adjustment. SO much easier.

But, I right now do have a custommade seating insert for the Dillon seating die, that was made to specifically capture the HAP bullet by its ogive for seating. A forum member in The U.S. who saw my plight made it for me, and it finally arrived recently after a LONG time in COVID-impaired mail processes at both the U.S. and Canadian postal systems! (after I had already bought, received, and installed the Redding die).

I might now install that custom insert, even though it will be much harder to set it initially to the COAL I want. If it reduces the base-to-.338 gage variation appreciably, I will then look at getting a local shop to modify the Redding insert for me, so that I can potentially have both stable OAL AND ease of adjustment!

Jim G

 

[Demi-human]

I might now install that custom insert, even though it will be much harder to set it initially to the COAL I want.

Just load all the stations and put a finished round in the seating station. Insert the new seating stem into the appropriate die body. Lower the seating stem down to the finished bullet.
Easy set.

Now use the reverse end of the caliper. Open it and set the long pin part of the blade on the die body and the measuring blade butt on the top of the seating stem adjustment knob. Viola!
Micrometer seating adjustments without a micrometer seating die.

 

[forrest r]

I have no idea why you keep thinking I'm telling you to modify your bbl???

If it was me I'd be looking a bullet that would be more suited to your bbl and your seating die. I like the 1 3/4r and 2r round flat nosed bullets myself. These are the 2 bullets I use for range play/target work.


The green bullet is a 125gr Mihec 640 series bullet. The red bullet is a 130gr lyman 35870 hollow based fn. Lyman came out with the 35870 design in 1900.

I use them in a 1911 that is supposed to be a NM 1911. Anyone can print anything on the side of a firearm, just because it's printed on it doesn't make it happen. My 1911 nm springfield armory range officer chambered in 9mm is no where near as good as your sig. but the $750 price tag for the ro reflects that. You get what you pay for.

My ro's bbl is throated and I chose those bullets above because they a a good fit to that throating. This aids in bullet/bore alignment increasing accuracy. Like I already stated my cheap springfield ro is no where near well made as your sig but I do manage to do 10shot groups like these @ 50ft.


Or these @ 50yds. the black target is 1 1/2"


The fliers on that 50yd target are from too light of a spring (8#), the slide wasn't getting a consistent lockup.

 

[murf]

that would be dangerous in this specific load.

that depends on the powder, some can be compressed and some cannot. i am not familiar with 3n38, but i'm glad you got the gist of my post.

murf

 

[JimGnitecki]

Just load all the stations and put a finished round in the seating station. Insert the new seating stem into the appropriate die body. Lower the seating stem down to the finished bullet.
Easy set.

Now use the reverse end of the caliper. Open it and set the long pin part of the blade on the die body and the measuring blade butt on the top of the seating stem adjustment knob. Viola!
Micrometer seating adjustments without a micrometer seating die.

That caliper idea is a nice suggestion! Thank-you! But it is not QUITE that easy, as the adjustment changes as you begin to tighten the die ring, because of the coarseness of the die threads. That's where the Redding die, with its separate micrometer controlled threads wins!

Jim G

 

[JimGnitecki]

I have no idea why you keep thinking I'm telling you to modify your bbl???

If it was me I'd be looking a bullet that would be more suited to your bbl and your seating die. I like the 1 3/4r and 2r round flat nosed bullets myself. These are the 2 bullets I use for range play/target work.
View attachment 986300

The green bullet is a 125gr Mihec 640 series bullet. The red bullet is a 130gr lyman 35870 hollow based fn. Lyman came out with the 35870 design in 1900.

I use them in a 1911 that is supposed to be a NM 1911. Anyone can print anything on the side of a firearm, just because it's printed on it doesn't make it happen. My 1911 nm springfield armory range officer chambered in 9mm is no where near as good as your sig. but the $750 price tag for the ro reflects that. You get what you pay for.

My ro's bbl is throated and I chose those bullets above because they a a good fit to that throating. This aids in bullet/bore alignment increasing accuracy. Like I already stated my cheap springfield ro is no where near well made as your sig but I do manage to do 10shot groups like these @ 50ft.
View attachment 986301

Or these @ 50yds. the black target is 1 1/2"
View attachment 986302

The fliers on that 50yd target are from too light of a spring (8#), the slide wasn't getting a consistent lockup.

This explanation with photos was very helpful! Is it a matter of trying different bullets with slightly different ogive shapes, or is there a more definitive criteria for the ogive shape?

 

[fxvr5]

that depends on the powder, some can be compressed and some cannot. i am not familiar with 3n38, but i'm glad you got the gist of my post.

3N38 appears to be okay with compression.
https://www.ssusa.org/articles/2018/1/9/how-to-use-9-major-in-a-short-barrel/

 

[Demi-human]

But it is not QUITE that easy, as the adjustment changes as you begin to tighten the die ring, because of the coarseness of the die threads.

What’s the difference?

 

[JimGnitecki]

What’s the difference?

BIG difference. TheDillon die is ONLY adjustable via the die thread, which is very coarse, and so allows movement of the die as it is being tightened by the lockring. The Redding die uses a separate very fine thread, in the die, ABOVE the seating insert to adjust the height, so you don't disturb the die lock ring at all, and the Redding adjustment is held strongly via an internal insert spring, so no separate "locking" step is required. It's a really well thought out system.

Unfortunately, the 9mm Redding seating insert's contact shape is not suitable for the HAP bullet, or any other hollowpoint bullet with a tip that is wider than approximately .210", because its passthrough hole for the bullet tip won't pass any tip larger than that passthrough hole size.

Jim G

 

[JimGnitecki]

3N38 appears to be okay with compression.
https://www.ssusa.org/articles/2018/1/9/how-to-use-9-major-in-a-short-barrel/

Yes, 3N38 is fine with compression, and in fact Vihtavouri's load table, which at maximum 3N38 powder produces "only" 1401 fps from a 4" barrel, and uses 8.7 grains of the powder, is marked by VV on their wesbite load manual as a compressed load. (I know because I was the one who emailed them about it when it was NOT marked as such, and they acknoweldged the omission and immediately marked it).

But even my 8.0 grain load fills the case to within about .15" of the rim, and unless I am very careful in my operation of the XL750, powder will spill during movement from one station to the next. (I am not ready to slow my pistol ammo production down to single-stage speed unless and until I get to an accuracy potential that warrants that extra precision versus speed tradeoff).

Brad Miller (PhD) has done excellent work with higher powered 9mm loads within the past year, but unfortunately, this specific article does not show ammunition accuracy representative of his normal work, because he apparently was limited in his readily available choice of pistol that would handle 9 Major loads. If you Google his other articles on higher velocity 9mm loads (NOT just "9 Major) in "Shooting Times" magazine, you'll find some amazingly accurate higher velocity loads.

Jim G

 

[Demi-human]

It's a really well thought out system.

Regardless the size of the threads, the distance it moves is just that.
What locks the Redding also locks the RCBS, friction.
If one can’t tighten it without movement, one can’t tighten the Redding, without movement.

All this is lost within the pulse in your wrist...