Donuts
- Thread starter fdshuster
- Start date
Say you are working with a factory chamber and unturned norma or lapua brass. With the larger degree of neck clearance will donuts still be an issue? Will it still be possible to detect them by dropping a bullet in the case? Would using a K&M or sinclair mandrel as final step before loading be enough to alleviate the problem in this case?
I have been using norma brass in a factory 7-08. I seat with a wilson seater. bullets are seated deep to magazine length. Sometimes I get the impression I am pushing past something at the bottom of the arbor press stroke. I have not however had any pressure issues. Could this be the dreaded donut?
I would love a pin gauge set but the prices out here (NZ) are crazy and they are very expensive to import because of the weight. Is there some other hole measuring device that can be used to detect them I had wondered about this
I have been using norma brass in a factory 7-08. I seat with a wilson seater. bullets are seated deep to magazine length. Sometimes I get the impression I am pushing past something at the bottom of the arbor press stroke. I have not however had any pressure issues. Could this be the dreaded donut?
I would love a pin gauge set but the prices out here (NZ) are crazy and they are very expensive to import because of the weight. Is there some other hole measuring device that can be used to detect them I had wondered about this
I want to thank fdshuster for bringing this topic up. I had a match this weekend and used a new .272 neck rifle for the first time. The rifle has 252 rounds fired and I started with new Lapua blue box brass. I have 4 firings on the brass and just checked all the pieces. Out of 54 pieces checked, 3 pieces allowed a complete no hang up slip fit of a Berger 80 flat base bullet in the fired neck. 8 others allowed a slip fit with a slight hitch and the rest would have required a 12 lb sledgehammer to get the bullet all the way into the case.
I took fdshuster's idea and used a small round jewelers file on an angle inside the fired neck and scraped away enough brass at the shoulder junction to allow the Berger 80 FB to slip fit easily in all cases. I never touched the actual seating area in the neck and cleaned the inside with a brass brush.
The reason I even checked this is because during the match I had a couple rounds with a noticeable heavier bolt lift after firing. 107 with 30.0 Varget, .003 away from lands. I remembered to set one of the rounds aside to check later and this piece had a noticeable donut. The funny thing is my 107 Sierra's were seated above where the donut stopped the bullet from slipping into the case. I checked on a Hornady ogive measuring tool with the 107 Sierra and my match rounds were about .050 longer than where the donut stopped the bullet in the fired case. I can't explain this. Oh and even more interesting - the round with the heavy bolt lift hit the 4" steel plate at 500 meters.
edited to add: I probably should have mentioned I use a Redding FL bushing die with .267 bushing, and set the shoulder back .002 each time.
I took fdshuster's idea and used a small round jewelers file on an angle inside the fired neck and scraped away enough brass at the shoulder junction to allow the Berger 80 FB to slip fit easily in all cases. I never touched the actual seating area in the neck and cleaned the inside with a brass brush.
The reason I even checked this is because during the match I had a couple rounds with a noticeable heavier bolt lift after firing. 107 with 30.0 Varget, .003 away from lands. I remembered to set one of the rounds aside to check later and this piece had a noticeable donut. The funny thing is my 107 Sierra's were seated above where the donut stopped the bullet from slipping into the case. I checked on a Hornady ogive measuring tool with the 107 Sierra and my match rounds were about .050 longer than where the donut stopped the bullet in the fired case. I can't explain this. Oh and even more interesting - the round with the heavy bolt lift hit the 4" steel plate at 500 meters.
edited to add: I probably should have mentioned I use a Redding FL bushing die with .267 bushing, and set the shoulder back .002 each time.
ttfreestyle
Silver $$ Contributor
mikecr said:
Thank you BoydAllen for the simple answers to my question. I have read many posts of yours , fdshusters and many others on here that have more knowledge than I. They have been very helpful for me and my family(my wife and twin daughters shoot as well) as we try to learn this great sport of mid/long range shooting. Since donuts were being discussed on this thread i thought it would be appropriate to ask a question as well(i did read this thread a couple times before i posted). I had more to say but i think a simple Thanks will do.
Donuts and bad habits, When forming cases as in going from 30/06 or 25/06 to 22/6mm Ackely Improved 'some kind of wildcat' I create donuts, when I ream a chamber with a sharp shoulder, I create donuts when cases are fired. Something about case stretch and or flow
Then there are bad habits acquired from the Internet.
F. Guffey
Then there are bad habits acquired from the Internet.
F. Guffey
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