I shot 60 rounds of previously loaded rounds that were loaded medium to maximum. Maximum being loads that were loaded 1.5 grains lowere than those where pressure signs were apparent. I then fireformed 20 cases the way I always do.
It is a 338-06 AI rifle on a 1909 Argentine action. When building this rifle, I personally cut back the bearing surfaces in the front ring to clean up any setback, squared the bolt lugs, and lapped the lugs and bearing surfaces for 100 % contact before reheat-treating. In allof my load development and fireforming, I have never had a single primer back out.
I always fireform with 14 grains bullseye and cornmeal using Winchester 30-06 bulk brass that I bought from the same lot so all the cases I'm using are, presumably, dimensionally the same. As I was fire-forming, I noticed that 7 out of 20 cases had primeres that backed out slightly. This has never happened before. When I say slightly, I am talking about .006-.009. I am wondering if I am experiencing set-back in my action.
I feel like a newbie even tough I have handloaded for years and have fire-formed mabye a thousand rounds of brass in my life. I have fired approximately 2500 rounds of ammo through this rifle with normal pressure signs appearing when maximum working loads are found. I don't hot-dog in handloading. I always avoid high preassures for my shooting and hunting loads.
Please, someone tell me what might be causing this to happen.
Thanks,
-Catter
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Shoot the largest caliber you can shoot well, and practice , practice, practice.
It may be setback, but in 99% of the cases this is a sign that your pressure is low.
The sequence goes like this. The firing pin moves the case ahead to the datum point, and starts ignition, at the same time. Pressure rises, the primer backs out against the bolt face, and the bullet starts moving.
Now, if the pressure continues to rise, AND HOLDS THIS PRESSURE LONG ENOUGH, the case will stretch until the head hits the bolt face. Upon which you extract the case, and you have a fireformed case.
I have played with this a little, and with fast burning powders, brass doesn't usually stretch to fill the chamber, even at 55,000 PSI, or thereabouts.
The cure to your problem, then, is to headspace off the bullet when fireforming. Seat firmly into the lands, and the problem SHOULD go away. Or, fireform with a slower powder, but then you are stretching the case at the head, which is not recommended.
Unless it is setback. HTH, Dutch.
Thanks for your input,
-Catter
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Shoot the largest caliber you can shoot well, and practice , practice, practice.
[This message has been edited by Wildcatter (edited 01-16-2002).]
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Life is more exitin' when yer stickin' suppositories inta a wildcats behind!
[This message has been edited by wildcat junkie (edited 01-16-2002).]
[This message has been edited by wildcat junkie (edited 01-17-2002).]
-Catter
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Shoot the largest caliber you can shoot well, and practice , practice, practice.
I have seen this happen a lot with people that use Unique and other pistol powders..Bullseye is the only dynamite for fireforming cases IMO.
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Ray Atkinson
Seems that the primer moved case forward, THEN the case expanded, griping the chamaber wall prior to full length case expansion.
Snowman's solution worked for me. A moderate load, cheapest bullet, seated so that It barely engages the lands. No more problem. Good luck!
Seems to me that if you go to the expense and effort of wildcatting and fireforming, a bulk bullet is not a signficant additional expense. JMO, Dutch.
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Life is more exitin' when yer stickin' suppositories inta a wildcats behind!
Thank you to all who posted,
-Catter
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Shoot the largest caliber you can shoot well, and practice , practice, practice.
quote:
Originally posted by Wildcatter:
I went to the range the other day.I shot 60 rounds of previously loaded rounds that were loaded medium to maximum. Maximum being loads that were loaded 1.5 grains lowere than those where pressure signs were apparent. I then fireformed 20 cases the way I always do.
It is a 338-06 AI rifle on a 1909 Argentine action. When building this rifle, I personally cut back the bearing surfaces in the front ring to clean up any setback, squared the bolt lugs, and lapped the lugs and bearing surfaces for 100 % contact before reheat-treating. In allof my load development and fireforming, I have never had a single primer back out.
I always fireform with 14 grains bullseye and cornmeal using Winchester 30-06 bulk brass that I bought from the same lot so all the cases I'm using are, presumably, dimensionally the same. As I was fire-forming, I noticed that 7 out of 20 cases had primeres that backed out slightly. This has never happened before. When I say slightly, I am talking about .006-.009. I am wondering if I am experiencing set-back in my action.
I feel like a newbie even tough I have handloaded for years and have fire-formed mabye a thousand rounds of brass in my life. I have fired approximately 2500 rounds of ammo through this rifle with normal pressure signs appearing when maximum working loads are found. I don't hot-dog in handloading. I always avoid high preassures for my shooting and hunting loads.
Please, someone tell me what might be causing this to happen.
Thanks,
-Catter
Wildcatter,
I too have fireformed a heck of alot and never had a poor result.i've blown out 06 straight using red dot or 700x using the corn meal method.i first anealed my cases to just below the shoulder.I used just a bit of tissue to cover the powder prior to adding the corn meal.make sure the corn meal is tamped down tightly especialy in the neck. I've used cases formed this way to make 9.3x62.they worked beautifully.I've also formed 7mmSTW from 8mm Rem.Mag.cases as well as 458 Lott from 375H@H.I think the packing down of the cornmeal is most important and just might cure your problem.
Richard
LET US PREY!
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rlda07052
Any insight on this? I was at the bench getting ready to load when I picked this damned article up. And just when I was beginning to feel secure about this procedure...crap! Maybe the Bullseye route is the better road to take, but I've been concerned about throat erosion; not because of anything intellectual on my part, but due to a worrysome imagination.
Just had another thought: When reforming with B'eye, even holding the rifle vertical, could the force of the firing pin move the case forward enough before firing to cause the overall case length to be shorter?
Man, these dreary, wet Saturdays are a sure prescription for cabin fever.
[This message has been edited by glenn (edited 01-20-2002).]
My other approach in radical wildcats is to load a reasonable full-power load with a scrap bullet and fire vertically. Works, but "vertical" necessarily must be a few degrees off of 90 degrees: what goes up must come down....
Paladin
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Life is more exitin' when yer stickin' suppositories inta a wildcats behind!
[This message has been edited by wildcat junkie (edited 01-20-2002).]
Dutch is on the money. The cause is in the case design. I get the same thing when I fire form for 30-06 AI. The lack of body taper reduces bolt thrust & allows the case to "grip" the chamber walls more than it would in a standard 30-06 or 338-06 chamber.
When I fire form for my 30-06 AI I run a 8mm expander ball in the 06 case. Then I neck size with the 30 cal expander ball but stay off the shoulder. This leaves a slight bump at the base of the neck so that the round chambers with a bit of "feel". When I reload for my 338-06 I use 35 Whelen brass so I can get that same bump at the base of the neck & get that "feel" when I chamber a round. This helps hold the round against the bolt face. hope this helps. It has worked well for me.
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NRA Life member
[This message has been edited by Bear Claw (edited 01-20-2002).]