Looking for a theory or answer

[Boz330]

Went to a silhouette match yesterday and 3 rounds in had a case separation. When I checked the other cases there was a line around the cases in the same area that was out of the ordinary.
The gun was a Ballard repro in 40-65. This gun has fired thousands of rounds with no problems. It hasn't been fired since this time last year. I was trying 58gr OE 3F under a Lyman Snover on a 060 Poly wad. The accuracy load for this gun has been 63gr of Swiss 2F but I ran out and have been using OE 2F in my 45-70 with excellent results and wanted to stay with 1 powder. The first OE 2F loads weren't coming around like I wanted and several folks suggested the 58gr 3F load so I thought that I would give it a try.
The separation was about an 1" up from the base. The chamber looks fine as near as I can tell and the separation was in the powder column not at the base of the boolit or wad. I haven't checked the inside of the other cases for an indentation where the line is or measured for length to see if they are stretched. From the looks of the case mouth I suspect that there may have been some stretching. The cases (WW) are old but have been annealed on a regular basis and are used in 3 40-65s all chambered with the same reamer with no problems.

Bob

[Don McDowell]

Any chance there was moisture in the chamber from either leftover from wiping, or from the blowtube not inserted far enough?

[Boz330]

Possible, but I use a 40-82 case specifically to preclude that. It seats very positively against the end of the chamber. Of course I could have gotten lax.

Bob

[Don McDowell]

Did the mouth of the case stay with the bullet and go down the barrel or did it just stick in the throat? If it went out the barrel, my guess is the bullet/wad was stuck to the side of the case and pulled it in two. If it just separated and stuck in the throat I would think it was moisture..

[4060MAY]

3F in my 38-50 pulls the end off the case, went to 1 1/2F either KIK or Ode E and the problem went away....I don't know the reason..I wipe and dry the chamber each shot

[Lead pot]

Bob.

When I have case separation near the base it's usually a head space problem. I find this more with cartridges that are bottlenecked or have a fast reduction like the .40-65 or the .44's I shoot formed from .45 basic cases or reformed .348 win brass that tend to have thin bases that have been reworked to a ticked diameter.
When brass is annealed, the heat will travel down lower if your not careful and soften the case lower to the point where the taper increases or the neck with bottle neck cases and this gets stretched when the powder charge goes off and holds the case at that point. If the rim recess is to deep and the block is a couple thousands back the headspace increases and shot after shot pulls the case wall at the point between the hard and soft case wall.
A tight neck tension will also pull case necks but more just below the bullet base. Case lube or excess bullet lube on bullets with exposed lube grooves that will get transferred to the chamber wall. Wet chamber will cause neck stretching but I have never had one stretch as low as what your cases are pulling apart.
I would check for a headspace problem. This can be checked out pretty easy with a brass rod long enough to fit into a unloaded case with the rod just a inch or two from the muzzle. Insert the empty case with the rifle laying in your cleaning cradle. Hold the case in with your thumb and insert the brass rod from the muzzle seating it the rest of the way using a pencil or dowel till it bottoms out still holding the case tight in the camber then take a depth gauge and measure the depth from the muzzle. Close the breach and take your dowel again and push on the brass rod so it pushes the case against the breach block face and take your second measurement to see how much it moved. This might sound like a long process compared to using a feeler gauge between the block and barrel stub, But it is more precise doing it this way.
You can use a wood dowel instead of the brass rod but make sure the ends are square.

[Boz330]

I have heard folks cautioning against 3F and heard it yesterday as well.
Don, the case stayed in the chamber but was a pain to get out.
Lead Pot, If I can find something that will fit the bill I'll try that method but this rifle was re-barreled by Wyoming Armory who seems to have a good reputation and I've never had a problem before. This rifle has fired several thousand rounds before. Which is why I'm puzzled.

Bob

[Lead pot]

Bob, I'm not laying the blame on your rifle or your technique the way you shoot. It's not so much as the rifle but the brass. My last order of .45-100 Starline brass I got I got case separation at the base, 1/2" above the rim. Below are some I took a picture of to sent to Starline. I never got a reply from them.
Those cases where shot less then 10 times.
I ended up scrapping 200 new cases.

http://i704.photobucket.com/albums/ww43/Kurtalt/IMG_2411_zpsu9eib1nn.jpg (http://s704.photobucket.com/user/Kurtalt/media/IMG_2411_zpsu9eib1nn.jpg.html)
http://i704.photobucket.com/albums/ww43/Kurtalt/IMG_2339_zpsylmw7wen.jpg (http://s704.photobucket.com/user/Kurtalt/media/IMG_2339_zpsylmw7wen.jpg.html)

[Knarley]

That brass looks kinda "long in the tooth" to me. Would age of the brass be a factor?

[EDG]

The sharp granules of black powder may be grabbing the inside of the case walls when fired.

I have seen a photo of a black powder charge exiting the muzzle of a rifle and it appeared to behave been burning from the rear forward.
My impression was that it looked like a burning dirt clod. The forward grains of powder get compressed out ward against the case walls so they grab the case walls as the powder moves forward. This stretches the cases. If your chamber is wet and your brass is polished the case body slides forward with no grab on the chamber walls stretching the cases.
None of these phenomena work the same was for all shots so you have some variation in the process.

You will note that this almost never happens with the smoother granules of smokeless powder.

[Boz330]

Bob.

When I have case separation near the base it's usually a head space problem. I find this more with cartridges that are bottlenecked or have a fast reduction like the .40-65 or the .44's I shoot formed from .45 basic cases or reformed .348 win brass that tend to have thin bases that have been reworked to a ticked diameter.
When brass is annealed, the heat will travel down lower if your not careful and soften the case lower to the point where the taper increases or the neck with bottle neck cases and this gets stretched when the powder charge goes off and holds the case at that point. If the rim recess is to deep and the block is a couple thousands back the headspace increases and shot after shot pulls the case wall at the point between the hard and soft case wall.
A tight neck tension will also pull case necks but more just below the bullet base. Case lube or excess bullet lube on bullets with exposed lube grooves that will get transferred to the chamber wall. Wet chamber will cause neck stretching but I have never had one stretch as low as what your cases are pulling apart.
I would check for a headspace problem. This can be checked out pretty easy with a brass rod long enough to fit into a unloaded case with the rod just a inch or two from the muzzle. Insert the empty case with the rifle laying in your cleaning cradle. Hold the case in with your thumb and insert the brass rod from the muzzle seating it the rest of the way using a pencil or dowel till it bottoms out still holding the case tight in the camber then take a depth gauge and measure the depth from the muzzle. Close the breach and take your dowel again and push on the brass rod so it pushes the case against the breach block face and take your second measurement to see how much it moved. This might sound like a long process compared to using a feeler gauge between the block and barrel stub, But it is more precise doing it this way.
You can use a wood dowel instead of the brass rod but make sure the ends are square.


Checked headspace the way you suggested and came up with .003 to .004 multiple times.
Feeler gauge indicated about the same.
I checked the inside of the cases that didn't separate and couldn't feel a definitive indent where the marks are but will scrap them anyway. The fired cases were .010 to .015 longer than un-fired cases in the same lot. I'm going to pull all of the loaded rounds and start over with 2F OE.
About all that I can come up with is to make sure to wipe the chamber before a match and also be very deliberate in seating the blow tube. Very possible that it was more than one thing that caused this. The old man always said I needed an occasional slap upside the head to keep me headed in the right direction.:shock:

Bob

[Larry Gibson]

How are you sizing the cases?

Larry Gibson

[kokomokid]

A .060 ldpe wad will grip a case wall if it is not supper clean. The 3f powder may help grip it.

[Boz330]

How are you sizing the cases?

Larry Gibson

Neck sizing then expanding to 408. Boolit sized 409.
Cases are wet tumbled with SS pins. Literally look like they are new inside and out.
The ONLY thing that has changed in thousands of rounds, is the 3F powder. And/or the possibility of lube/water on the chamber wall. You get in a routine and follow it to the point that it requires no conscious thought and maybe I screwed up.

Bob

[jonp]

I am not an expert in this by any means but it would seem to me that if everything is the same for thousands of rounds and you changed only one thing and had this happen you have a likely culprit.

[rfd]

long ago i had been told by a few bpcr gurus to make sure the case insides were all clean and shiny, so that the bp won't grab the brass and stretch it and possibly cause separation. the insides of my fired and sonically cleaned brass shines like the sun.

http://i.imgur.com/UVwFd0F.jpg

http://i.imgur.com/2Sf5Iea.jpg

i also don't work the fire formed brass at all for reloading. with new .45-70 brass i check the length and then lube and expand the mouth with a baco .461 or .462 straight wall expand plug in a lyman 'm' die body. this simulates fire formed brass. on the reload, and after thorough cleaning, the only time the brass goes on the press is for the powder compression plug. i've checked the brass (starline) during the course of many reloads and none have had any significant length increase, if at all.

[Boz330]

I am not an expert in this by any means but it would seem to me that if everything is the same for thousands of rounds and you changed only one thing and had this happen you have a likely culprit.

Kind of my thinking. As soon as deer season is over I'll get to working on it.
Right now Bambi for the freezer is the only thing on my mind. I hunt with a BPCR built by me from extra parts, cast boolits and my homemade BP.:bigsmyl2: Adds a little challenge to it.

Bob

[sharpsguy]

3f OE and a poly wad is a recipe for case stretching and/or separations. Get rid of the poly wad and go back to 2f and your problem will disappear.

[rfd]

wow bob, a most beautious li'l roller ya got there ...

http://castboolits.gunloads.com/attachment.php?attachmentid=153067&d=1346617733

[Boz330]

Thanks, 40 cal barrel from a highwall I had rebarreled, Swede 8MM roller action, and Treebone stock. I was tickled the way it came out. I usually can't summon that sort of patience, especially fitting that curved butt plate. Toughest part of the whole job.

Bob


wow bob, a most beautious li'l roller ya got there ...

http://castboolits.gunloads.com/attachment.php?attachmentid=153067&d=1346617733

[Gunlaker]

For those of you who have not shot breech seated bullets you might find it interesting to hear that case stretching is not at all uncommon whith black powder, even if the headspace is perfect and the cases are shiny clean.

In my experience the finer grades of powder are far worse than the coarse ones. And thin brass is worse than thick. As an example, in my CPA using long starline .38-55 brass ( which is much thinner than most rifle brass averaging only 0.0075" at the mouth ), and Goex FFFg Express, cases will only last 3 or so firings before being stretched to the point of separation. The same rifle using FFg shows only minimal stretching, and Fg shows no measurable stretching. Only a thin card wad is used to hold the powder in the case, and compression is very near zero.

My .32-40's will generally go hundreds of firings on the same case when loaded with FFg. They have the advantage of thicker brass ( 0.0105" or so ). Some use custom "everlasting style" cases which are far thicker and eliminate stretching.

Just a few thoughts from a different shooting discipline for another perspective.

Chris.

[Larry Gibson]

3f OE and a poly wad is a recipe for case stretching and/or separations. Get rid of the poly wad and go back to 2f and your problem will disappear.

I agree that the case stretch is probably cause by the poly wad gripping the case wall and pulling it forward. Not sure the 3f exasperates the problem. Suggest eliminating the poly wad first and test with 3f on a couple cases to see.

Larry Gibson

[Chill Wills]

I agree that the case stretch is probably cause by the poly wad gripping the case wall and pulling it forward. Not sure the 3f exasperates the problem. Suggest eliminating the poly wad first and test with 3f on a couple cases to see.

Larry Gibson

OK. So I have a question - two really; What is it about a poly wad that pulls a case apart? What is different about the loads that use poly wads and pull the case apart and all the loads that use poly wads and work normally?

The first question assumes substituting a Veg wad or a card wad or am I wrong about that?

Thanks, Michael Rix

[sharpsguy]

The poly wads expand radially upon firing and grip the case walls really tight, causing the stretching/separations. The fiber and card wads don't have the same radial expansion and don't damage cases. My take is that the guys using poly wads that have so far not had problems have simply been lucky thus far. I also doubt that many of them are using 3f in 45 caliber cases.

Where I have seen the problem manifest itself the most here at my range has been with guys shooting the longer straight walled 45 caliber cases. The old stretched brass in 45-90 from Buffalo Arms is prone to separating when used with poly wads, and I have seen it several times in Starline brass in 45-100 and 45-110 as well. I have never seen a case separation in a 40-65 or in the big 45 calibers when a Walters vegetable wad or a wad cut from milk carton is used.

[EDG]

You can always test the poly wads with a static load.

The area of a .458 bullet base is .165 sq inches.

Assuming your loads develop 20,000 psi means you have a about 3300 lbs applied to the poly wad trying to expand it.

[Boz330]

I have used poly wads for at least 5 years now and have never had a problem till substituting 3F. Not being an expert on internal ballistics my take would be that the extra oomph from the 3F powder might just be the straw that breaks the camel's back. I have no problem trying the veggy wads. The poly wads just gave me a little smaller group way back when I started testing them.

Because of limited time I tend to stop testing when a load gets to a certain level of performance. There might be more accuracy that can be gotten but a 1MOA load in my 3MOA hold isn't going to get me anywhere.

Bob

[Don McDowell]

Bob are you buying those poly wads or punching them. The reason I ask is I notice one wad supplier is punching his 45 caliber wads at .462,,, that's just a tad on the large side seems to me, and could create some problems with the stiffer poly.

[rfd]

tried poly wads, both commercial and punched, prefer milk carton - and paper/wax is easier on the environment. :smile:

[Don McDowell]

tried poly wads, both commercial and punched, prefer milk carton - and paper/wax is easier on the environment. :smile:

Well you know that's all fine and dandy if you're mostly a recreational shooter that goes out and bangs a steel target or punches few holes in a handmade paper target now and again. But this thread was started by Boz who by most accounts is a fairly serious bpcr competitor, there's been input by one shooter that has his name on the Castle trophy at least once, and has won a ton of matches, as well as another guy who in the past shot some really serious stuff and loaded serious ammo for his wife to win a wall full of trophies.
So until you've lost a national title in your class by a mere 4 pts, or a single x it's hard to fully understand why folks don't give much concern about easier on the environment,, What their rifle and the target tell them is best is what they're searching for..and like Boz said in post 26, his polywads gave him the best groups for several years , and now he's trying to figure the problem with case separation.

[rfd]

well there ya go again, don - you always seem to know what's best for everyone, but for the record, i never said poly wads weren't good or bad news, just stated what i prefer since someone started talking wads in this thread. and did you not did see the smiley face at the end of my last post? it's truly great that there are so many elite, world class bpcr shooters who humbly both share and contribute on this forum. :cool:

[Don McDowell]

Yes it is nice that the likes of Michael Rix, Bill Bagwell, Kenny Wasserburger, Rick Mulhern and others do show up and give their thoughts and share experiences.

[rfd]

Yes it is nice that the likes of Michael Rix, Bill Bagwell, Kenny Wasserburger, Rick Mulhern and others do show up and give their thoughts and share experiences.

yessir mr don - on that, i totally agree and am most appreciate to them all.

[Gunlaker]

Bob, I would guess that it's the FFFg if everything nothing else has changed. Unless your cases are really old and need annealing. After all of my testing in BPCR and chuetzen rifles I'm pretty confident that finer powders are harder on cases. I use poly wads pretty much exclusively in my BPCR rifles. I have had some nice results with FFFg Express in the .45-70's and no stretching with 0.060" LDPE wads, but usually use finer powders. The OE stuff is pretty hot too. Chris.

[Gunlaker]

Bob, on more thought, if using OE in the .40-65, you might want to consider the 1.5 granulation. It sounds odd to use a coarser granulation in the smaller cartridges but it does work. I'm using about 60.6gr of OE 1.5 with the 400gr Kidwell Money bullet. MV is 1298 fps and accuracy is quite comparable to my previous load of 58gr of Goex FFFg Express and the Saeco #740 bullet. I don't remember the velocity stats, but they are not so different from the OE 1.5 load surprisingly.

Both of these loads are easy on cases ( both use LDPE wads ) as I've not lost one yet in several thousand rounds through this rifle.

I know it doesn't solve your mystery, but I thought it might be useful information to you.

Chris.

[rfd]

bob, it sure sounds like the smoking gun is making the change to 3f. hope you get it all worked out.

[EDG]

You can always isolate the problem.

Shoot 25 or 30 round of 3F with no poly wads.
If the problem stops then it may be the poly wad or the combination of poly wad and 3F.

[Boz330]

You can always isolate the problem.

Shoot 25 or 30 round of 3F with no poly wads.
If the problem stops then it may be the poly wad or the combination of poly wad and 3F.


The 3F was a suggestion from several top notch shooters and made sense to me so I tried it. Because of time constraints I took it to a match without testing, not the first time I have done that, but it was a long drive to just turn around and head home. There is a lot of knowledge and experience here which is why I asked. Usually that light of a charge of BP shouldn't be a problem, but obviously was. I appreciate all input and try to evaluate it for my use.

BTW Don, I punch my own wads with a Buffalo Arms punch.

I've been deer hunting so have been away from a computer for several days. Kinda nice actually, no TV or Computer, but came back to reality by finding out the rag heads killed a bunch French folks. I was wondering why all of the flags locally were at half staff.

Bob

[Ballistics in Scotland]

The sharp granules of black powder may be grabbing the inside of the case walls when fired.

I have seen a photo of a black powder charge exiting the muzzle of a rifle and it appeared to behave been burning from the rear forward.
My impression was that it looked like a burning dirt clod. The forward grains of powder get compressed out ward against the case walls so they grab the case walls as the powder moves forward. This stretches the cases. If your chamber is wet and your brass is polished the case body slides forward with no grab on the chamber walls stretching the cases.
None of these phenomena work the same was for all shots so you have some variation in the process.

You will note that this almost never happens with the smoother granules of smokeless powder.

I think you have something here. 1in. from the base doesn't sound like the usual form of lengthening through brass movement, which Leadpot's appears to be. In 1910 Dr. Franklin Mann, author of "The Bullet's Flight from Powder to Target", experimented with a presumably condemned barrel, by placing a considerable quantity of sand between powder and bullet. The idea was to separate the effect of a low charge from the effect of an airspace. But what he got was case-necks torn off and carried down the bore. Sand appears to lock to itself and to the case-neck under impact, just as dry sand will stop a bullet in less distance than when it is lubricated by dampness.

I have had the same thing happen with an unwise reloading practice though an unsuspected one, with the 8x60R Portuguese. British black powder was going through a phase of inferiority, and gave 1200ft./sec. instead of the factory 1700. A Reloder7 load which gave 1700 showed low pressure indications, so I reduced it slightly and filled up the case with black. But what I got was the neck separation, with primer deformation which showed pressure still wasn't high. I am sure it worked in the same way as a sand blockage.

But all this begs the question why they don't all do this. I think something (in my case perhaps the poor quality of the black powder) has to stop it from igniting properly. Is it possible that you accidentally loaded the poly wad before the powder, or more likely (since there must have been some powder behind it), it tilted and let some powder get ahead of it?

I could imagine much thicker poly wads getting a dangerously tight grip on the case neck, as various authorities have reported rubber can. In striking contrast to cork, which compresses lengthwise without even as much lateral swelling as you want to make a seal, rubber simply tries to change one dimension reducing into another dimension expanding. But I can's see such thin poly wads having that effect.

[Larry Gibson]

You can always isolate the problem.

Shoot 25 or 30 round of 3F with no poly wads.
If the problem stops then it may be the poly wad or the combination of poly wad and 3F.

+1 again restating an earlier suggestion. I have shot a lot of straight 70 gr GOEX Cartridge or FFFG BP and duplex loads (7 gr 4759 under 54 gr GOEX Cartridge or FFFG) with 405 and 500 gr cast bullets w/o a single hint of this problem I also extensive tested .003 and .006 veggie wads and milk carton wads (compressed between bullet and powder) and never could discern any improvement in accuracy with the wad. Subsequently I haven't used such a wad in many years.

Larry Gibson

BTW; not wanting or looking for a discussion on merits of wad use, just stating my own experience and preference.

[Don McDowell]

BTW Don, I punch my own wads with a Buffalo Arms punch.


What diameter does it poke out the ldpe wads? I found with my 44's going with a wad over .447 didn't help much, matter of fact it seemed to make the groups expand..

[semtav]

155075Sometimes its not the gun or the cartridge but the idiot behind the gun

[Boz330]

155075Sometimes its not the gun or the cartridge but the idiot behind the gun

Your point????????????????????

Bob

[semtav]

Had only the two middle cases cracked, I too would have thot I suddenly had defective cases. but it was moisture that caused it. It could be something as subtle as some lube from a shell seated out so some of the grooves are showing that causes it.