Neck tension on revolver loads

[44man]

I decided to do a quick test for you about neck tension's effect on groups. Bad move today because it started to pour down rain right in the middle of shooting. I am soaked, glasses full of water and my red dot has water on the glass. I had to shoot fast.
Anyway, the brass was new, unfired. I found a large difference in seating pressure as I measured each. Not a good thing using unfired brass either because the back of the case's are smaller then the chamber, but I had no fired brass ready. I neck size fired brass.
I had five shots that were the same and shot them last. The first target is a mix of all the other neck tensions. You can see all of the different points of impact. I quit trying to mark them when the rain came.
I used my .475 BFR with the Lee 400 gr boolit, 26.5 gr's of 296 and the Fed LP mag primer. All loads were the same except the tension. The last group was not as good as usual but the Lee boolit doesn't shoot as tight as my own boolits. I was out of anything else and need to cast. The thing is that it shows why most of you have poor groups when shooting your best. You blame the gun, the load and your shooting when it is the brass itself that is causing your large groups. The dies you use have a large bearing on groups.
I will test more for you when I make more boolits and the weather is better but in every instance, you will see that neck tension will make or break groups.
Stop blaming yourself or your guns!
You can see the water on the last target and it was in my pocket.

[Poygan]

I have wondered about this neck tension issue when I am flaring the necks and find they vary from loose to very tight. I've noticed this mostly in .357 brass and in truth I doubt my shooting is sufficiently good that I could distinguish the results at the range. I think I need to experiment with my Contender with the 4X scope. That may give me enough consistency to note any variations.

[44man]

Your shooting may be a LOT better then you think it is! There is more to this then a good hold and trigger break.
I have posted pictures and an explanation on how to measure the seating pressure, long ago. If you feel a difference in expanding or seating, there is a problem and you will not group. Remember that the press handle is powerful and what you feel is way less then actual. YOU CAN'T GO BY FEEL!

[danski26]

44man

How are you adjusting "neck tension" on straight wall pistol cases? I looked for a bushing type die for them just now online and did not see any. "not a thorough search on my part." Do you use a bushing die?

Do you vary neck tension using a taper crimp die? Or do you mean you vary the amount of crimp you put on a case with some other type of crimp die?
Or are you doing somthing completely different?

Dan

[44man]

Dan, you can't change the case. I measure how much force it takes to seat each boolit and sort them. I have a bench rest type die for the .44 but rarely use it. The Hornady dies get close enough for decent loads.
There is just no way to predict springback between cases. No two pieces of brass are the same.
Crimp has no effect at all! I have tested this thousands of times.

[Buckshot]

.............Boolit grip/neck tension is definately important. Dean Grennel had put up some 44 mags using H110 and they were duds. Several lodged boolits and all had incomplete combustion to one degree or another. He took the balance of them home and discovered he had (in his words) a crimp you could choke a rabid weasel with, but caseneck tension was very casual.

Found out his dies and that make of brass was not compatable. Dis and re-loaded with brass sized in different dies producing a good grip and it made a world of difference.

..................Buckshot

[Bass Ackward]

Well I just completed some very extensive size testing on neck tension over the last year. I manufactured dies to neck size a 44 for .002, .004, .006, and .010 neck tension. I used new cases and old, standard and a magnum primer, Unique and 296. A light bullet (short case seating depth) and a heavy design.

What I was hoping to find: Some magical relationship for sizing that could eliminate all other options and ensure that if I just met this criteria, I would be guaranteed of "my" best accuracy and make this one less step to worry about.

What I learned: Essentially the test was a waste of time and components for anything other than education. Case anneal made much more difference to grip than any specific dimensional size. In other words, I could make any size work altering combinations (or fail) up and down the line if I played with anneal. Think about it. Change how strong something is and you change the grip, thus you change what sizing you need. The best area was .002 to .004 grip regardless of the combinations.

What seemed more important was that the anneal or the sizing establish and maintain 100% bullet contact. Change my case flair for seating or my crimp, and I changed my grip requirement and possibly the need for a different anneal or size.

Once the .... ideal point was .... sufficient for the pressure range and powder speed you chose, your best grouping occurred. Any further reduction or anneal had minimal effect and acted like hotter primers and would actually start opening groups.

So this explained why I saw great improvement a couple of years ago by changing case anneal on lower pressure loads.

[Lloyd Smale]

guess ill stick to my 1-2 inch groups at 25 yards as i shoot at least 500 rounds a week in the winter and at least twice that in the summer and i just dont have time to fool around with case anealing. Hell i dont even sort brass anymore. The accuracy i get out of a gun surfices for any hunting situation and has netted me many a trophys in competitive shooting and id rather shoot then fool around with alot of extra loading techniques. A guy doesnt learn to shoot standing over a casting pot or a press and ive yet to see where a handgun that shot one inch at 100 yards was more effective in the field then one that shoots the same at 25.

[44man]

True, what you did was to make case tension even from shot to shot. I would say this is the most important thing for accuracy but one of the hardest things to control. I have tried everything possible from annealing, (Not good with the heavy boolits and loads I use.) to bench dies with a variety of collars along with a special tool to measure springback after sizing.
I know all of you understand that different release poundage of a boolit can change internal ballistics from shot to shot, making the SD's and ES's go wacko. It is the reason I get a super tight group one time and a little wider one the next because the brass from the tighter group was more even. I have been lax measuring the seating pressure because the Hornady dies work the best. The expander is correct and only enters the case a short distance, leaving most of the sized portion unexpanded. However, there is still a difference but it is smaller then other dies provide.
When I started IHMSA, I had trouble getting groups and found the problem by accident. I was feeling different bullet seating forces with the strong press handle. I kind of went crazy trying to figure it out and came up with an easy way to measure it. I was astounded at the different points of impact between tension differences. Some were as much as 10" difference---YES, 10".
I also found that new, unfired brass can be worse then fired brass. I think work hardening can even out the brass a little. This is contrary to one fellow that says he only shoots IHMSA with new cases. Is it true? I don't really know but it works for me. I have brass shot 40 times that is still very accurate.
While doing all of this work, I played with crimps from none, shooting one shot at a time, to the hardest profile crimp I could apply without buckling the brass. There was not enough difference to worry about.
Another thing I have been lax about is keeping track of how many shots each case has. But measuring the seating pressure and sorting eliminates the differences.

[felix]

Excellent, you two folks. Well written and easy to understand. ... felix

[danski26]

Wow.....I must be an idiot if that was easy to understand!

44man

What method and tools/gauges do you use to measure "neck tension" on a straight walled case?

I understand the neck tension issue, I have special dies and tools to change neck tension for my high power shooting. Glen Zediker does a very nice job explaining the issues involved in his "Handloading For Competition" book.

The tools and dies I have are not compatable to.....lets say 44 rem mag. I have difficulty understanding what you mean by "necks" on a straight walled case? At firts I thought you where refering to the rim that is crimped, one way or another into the boolit. But it seems that you are talking about the portion of the case UNDER that.

Again my questions are:

How do you measure the "seating pressure"?

How do you change the neck tension on 44 rem mag? (neck, not being part of the crimp)

How are you measuring this tension?

What affect are you seeing with this variance?

Are you "turning" this neck portion of the brass inside and out for uniformity before adjusting tension?

This is a very interesting topic. I have not thought of neck tension as a factor with straight walled cases and am sincerly looking for info.

[lar45]

Thinking back I belive that I was useing Win brass in my Taurus 454 nose tests. I had a problem with Win cases back then with some factory loads splitting cases. I think that I annealed some of the cases trying to keep them from splitting, but they probably got mixed in with the others.
I have a new box of starline cases. I'll try and shoot them all once and then do the nose comparison over. I didn't shoot enough rounds of each on the first test to really get an accurate measurement, but I think it was close enough to get an idea of which meplat size and nose shape worked better. The bore rideing and trunicated cone didn't shoot well at all. The ogival flat point with 70% nose seemed to do the best overall. The 80 and 90% noses were almost as good. The modern SWC shot well but the Keith style was all over the place.

I did switch to the Lee factory crimp after a roll crimp from RCBS dies and it lowered the velocity spread. this could have been caused by the brass getting more uniform from shooting?

I have a .451" 18"long blank and have been thinking of putting it on a mauser action to do the test again. It's easier for me to hold a rifle still and it would probably take alot of the nut behind the trigger factor out of the results.

[44man]

Give me a little time. I will explain the best I can and post a picture. It is not the ultimate but will improve accuracy enough to make it worthwhile.

[fourarmed]

After reading what Bass wrote some time back about annealing, I tried trimming and annealing all the Starline .41 brass that I use in my DW silhouette revolver. I have no scientific data, but I shot a 37x40 in the first match this year, which is the best I have done with this load. On the other hand, it may have been the yoga. I will continue both.

[44man]

Bass is good and does as much work as I do, maybe a little different direction but he also gets results. The difference is that I use heavy boolit, heavy charges for hunting. Annealed cases can pull all of the boolits for me. It is very hard to control the anneal. Need an electric annealer system. Bass, thats your next job.

[44man]

OK, again. Here is my system. See the spring steel rod held on my press handle with a hose clamp? I drilled a hole in the handle and there is a short rod, graduated, with a faucet washer on it, going through the hole. It is held to the long rod with a simple wire link that can slide. I barely start the boolit with the press handle and then seat it fully with the rod. It bends and the washer will slide out on the short rod and stay at the graduation for the seating pressure of that round. I put that round in the pile for that graduation. I push the washer back for the next round. Very, very easy and effective.
Danski, you can't change the tension! Never turn or ream brass for the revolver unless you make cases from some other case. You need the thickness.
Accuracy is increased in straight wall cases by keeping the expansion to a minimum. I like to see the base of the boolit and grease grooves through the brass, that is tight! Dead soft boolits will be a problem. I do NOT do this with soft boolits and black powder in the BPCR!
When I size with my Hornady dies, I only size to just below where the base of a seated boolit goes. Neck size, so to speak, and only full length when it gets hard to chamber, then go back to neck sizing. This keeps a good fit at the rear of the case. Makes for better boolit alignment.

[danski26]

Very interesting. I'm guessing that instead of controlling like is done on a bottle neck case you segregate. Kinda a high, middle and low "seating pressure" piles approach. Very interesting.....thanks for the explanation.

[danski26]

Lets give values to the tensions in a loaded round. I will use the algabreic terms of "a,b,c,d.....ect"

If the brass below the crimp is squeezing the boolit at "a" psi and the crimp is squeezing the boolit at "a + unknown" psi, why would the squeezing below the crimp matter? You have already stated that the crimp does not mater. So the crimps "a+b or a+c or a+d....ect" does not matter but the case below the crimps "a or a+b or a+c or a+d....ect" does matter????

I did a quick test today at the range. loade 20 round the way i normaly do for 44 rem mag, 250 gr KT boolit and a load of h110. Then i did another set of 20 with no crimp only a straight wall with the projectile pushed in by hand. I single loaded and shot these by neccesity. The single loaded rounds had a much different "tension" on them than the normaly loaded round.

I was only hoping to see some difference, good or bad with these samples.

When you say crimp does not matter....I believe you. I saw no difference in these two samples.

How can I set up the experiment better? Anyone have any sugestions?

[44man]

One of the easiest ways is to polish the expander a little to make the boolits fit tighter. This can help. The best way is to make a way to measure the seating pressure since there is no way to measure the pulling pressure.
There is not a whole lot of difference in actual accuracy if cases have a looser tension or a tighter tension. As long as all have as close a tension as you can get, they will shoot good. POI changes a lot though, between tight and loose and if mixed, groups can get very poor.
Using a slow powder like 296 or H110 should be on the tight side. Faster powders can do very well with looser cases.

[Uncle Grinch]

When my .45 ACP brass gets loose and loses it's grip, I run it thru my .308 die just enough to tighten it up. It works great.

Maybe there's another combination for the .38/.357 that you can use to bring them down a little.

Just a thought....

[cbrick]

Great thread. 44man's testing almost mirror's my own and I agree with him completely on most points.

In a revolver the crimp has very little to do with grouping, more to do with bullet pull under recoil. Here is the results of a test I ran on bullet pull in virgin brass, sized brass, crimped brass and no crimp at all. FA 357, 190 gr cast GC, WW alloy with 3% tin, HT to 18 BHN.

Profile crimp, second firing of WW brass, Carbide die sized
E.S. 30
A.V. 1518
S.D. 9

Roll crimp, second firing of WW brass, Carbide die sized
E.S. 30
A.V. 1520
S.D. 9

No crimp, second firing of WW brass, Carbide die sized
E.S. 30
A.V. 1528
S.D. 9


Lite profile crimp, virgin WW brass, not sized
E.S. 26
A.V. 1532
S.D. 8

My normal profile crimp, virgin WW brass, not sized
E.S. 26
A.V. 1536
S.D. 8

Sorry I don't have the groups to go with the chrono numbers. None of the bullets pulled during this test and I shot four and then measured the cartridge OAL of the fifth round before firing it in each test.

The one point that I disagree with 44man on is the virgin brass. The very best groups I get from a revolver are with virgin, unsized brass, length trimmed, flash holes uniformed and primer pockets uniformed to the max depth of the Sinclair tool and a very minimal case mouth flare. The more times the case is fired the larger the groups. All of my major matches are fired with virgin, unsized brass though I do use fired brass at other times just to keep the amount of brass prep down. I haven't yet tested annealing straight walled pistol brass even though I have a brand new Ken Light annealer (for about two years now) that I got for this very purpose. That project is still on the roundtoit list.

http://www.lasc.us/DSCN1316-5.jpg

That shell plate is for the 357 brass, great machine, extremely well made. I really need to start using it.

Rick

[44man]

Cbrick, I think it depends on the brass and who made it. I made the statement after measuring the seating pressure with unfired .475 Hornady brass. I get a wider variation then after it is fired once. I have never checked this with my other calibers, never thought about it before. I don't get tight groups with the new Hornady brass either. Thats when I decided to see what was going on.
I have no idea who makes the brass for them or if they make their own. It seems a little soft.

[dubber123]

44man, I have nothing to compare it to, as far as how soft it is, but my Hornady .475 brass lasts and lasts, I have shot mine many many times, almost exclusively with a 440 gr. at 1,300+, (4-3/4" barrel), and I have yet to lose a single piece. My dies are Hornady, and I couldn't see a better set of dies. Like you mentioned, I can see all the lube grooves and the bullet base through the brass. The tight chambers in the F/A might be responsible for the long case life, but I can say I really like the Hornady brass.

[felix]

Brass lots vary all over the place. The only way to compare each individual piece is to see where it places in the group. Some cases are heavy and soft, and some are light and hard. Both seem to group into the group. So, you really must shoot to decipher which cases go with what load and gun combo. Does it matter? Yes, for the long shots at small targets. Personally, for me, a revolter cartridge gets no respect and targets are therefore large, and distances short. In other words, pie plate at a hunnert. Not so with BR stuff, for real or for pleasure. ... felix

[44man]

I didn't say the brass was bad, I like it and it does last. It's just the first loading, after that, groups come in good. It just might be the lot I have, like Feilix says.
I just never paid as much attention before.

[dubber123]

44man, rest easy, I wasn't saying you were wrong, I just said I really like the .475 brass in my limited, (compared to yours) experience. I definately have favorite brands, and some really seem to lose neck tension quicker. CBC and Rem. brass in .45 auto get noticeably loose much quicker for me than other brands, enough so I have a small pile on my bench I have to shoot out of a revolver, because I don't dare run them through an auto, the bullets too loose. The Hornady .475 is super consistant for me, which may expain why it shoots so well for me.

[G. Blessing]

amazing..... absolutely amazing the thing that I learn here...

G.

[cbrick]

Cbrick, I think it depends on the brass and who made it.

Could very well be. This is something that I have only tested in the 454 (FA brass, dunno who made it), 357 mag (IMI, Rem & Winchester brass), 41 mag (Starline & Rem brass). It's something that I picked up from the guy that has won more International, National & State master class revolver championships than anyone. He shoots 44 mag mostly with a Dan Wesson and is something that he did a lot of testing on many years ago.

Rick

[Char-Gar]

One of the best pistols shooters and loader I know is Jim Taylor. Jim does not use an expander at all. He resizes his cases, bells the mouth and seats the bullets. His loads look like the snake that swallowed the pig, but they shoot very well.

[Bass Ackward]

One of the best pistols shooters and loader I know is Jim Taylor. Jim does not use an expander at all. He resizes his cases, bells the mouth and seats the bullets. His loads look like the snake that swallowed the pig, but they shoot very well.


Yep. That was exactly how I did my sizing for testing. No expander, just bell them. But that also created a run out problem.

What was interesting to see was that bullet run out increased as the requirement for seating pressure increased from smaller sizing. I assume this is a problem because of the extra .... space in dies necessary for seating larger than standard diameter bullets.

If your nose punch is not a "perfect" fit and or your bullets deform slightly, you have what amounts to slop. Since I usually use a flat punch seater, I live with the slop.

What helped run out as an unexpected result came from the use of a Lee factory crimp die. If used lightly, the factory crimp die would actually decrease bullet run out. Key word there was decrease. Question was what bent back into alignment?

Never expected that. But it could certainly explain why some people see monumental improvements in accuracy and swear by it thinking it is the crimp while others say it is a waste of time.

So again, if something solves a problem that we create through loading, then success follows use. If sizing is your your best horse , I say ride it. The end result is what counts.

[Blackwater]

This post made me think back to when I was younger, and shooting a VERY large amount of pistol rounds, almost all with cast. I use an old Reloader Special NON-compound leverage press, and though I've had several Rockchuckers along the way, none have given me the accuracy with either j-bullets or cast from rifle or pistols as that old RS press. For a time, I just thought it was because the old RS had better alignment than the others I'd had and tried.

Now, after reading this, I realized that whenever I was reloading, and felt any unusual pressure in the handle, or lack of it compared to what the bulk of my loads were giving me, I'd take that round and use it as a "cull" for just plinking or position shooting for fun after the load testing sessions.

I've had my ammo used in others' rifles and pistols, and often my loads, even using the exact same components, outshot the other guys' loads in HIS gun.

Can't help but wonder if that non-compound leverage hasn't been "notifying" me via more sensitivity at the handle, when there's some factor that would tend to increase runout and/or neck tension.

Also, FWIW, since I started using the Lee case spinner and trimmers, after trimming, I run some 0000 steel wool over the mouth and polish it after trimming, chamferring and deburring. This helped reduce the number of times I'd be able to feel a pressure difference on the handle of the old RS press, and it has eliminated at least a good portion of my unexplained shots out of the group.

Ain't reloadin' FUN!

[44man]

That is how I found the problem so many years ago that I won't even say, the press handle feel. I was using the huge RCBS, A2 or whatever it was, and still felt the difference. Thats when I started my testing.
I have tried cleaning the inside of the brass without any drastic change in measurements, it just isn't felt as much. My new .475 brass does show the difference even with shiny insides. I won't be the one to say that polishing the inside of brass will correct the tension problem. They way they come from the tumbler is good enough for me. It might help with jacketed to even things a little, but remember we are seating grease balls.