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Stiff bolt lift

berryreed

Private
Minuteman
Oct 7, 2010
12
0
70
WY
I am using 338 Remington Ultra Mag brass. I notice that after I have fired my brass several times that I begin to get a stiff bolt lift. If I use the same lot of brass that is new, I do not have this problem. Yes I am full length resizing. Your thoughts appreciated.
 
Re: Stiff bolt lift

You mentioned the you are full length sizeing, but are the shoulders getting bumped?
Do you struggle to close the bolt intitialy, either that or you are at max charge weight, try backing off .2 from your load.
 
Re: Stiff bolt lift

I'm with Memo. My guess is you may not be bumping your shoulder back enough (die set up issue). Of course, you would feel that upon bolt closing on a round, not just on the lift.
Anyway, are you measuring your shoulder bump? The Sinclair Bump Gage insert system is an easy one to use (there are others though).
General advice is a .001 to .002" bump for bolt guns -- I typically do .002 to .003" for bolt, .003 to .005" for gas guns.
 
Re: Stiff bolt lift

Shoulders are getting bumped. Round chambers easily. I have this problem even with several grains less of powder. I do not clean my cases after each firing, but I do check case neck length. I turn the case necks after the first firing. I have noticed that after several firings there is a slight rise in the area of the neck and shoulder junction.
 
Re: Stiff bolt lift

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">
Have the cases grown in length causing pressure to build up from case neck biting down on projectiles when chambered? </div></div>
do you have any that have not been fired, maybe there is a build up of material some where. Overall length, I'm scrathcing my head trying to figure out, sorry couldn't help much. Hopefully someone can chime in.
 
Re: Stiff bolt lift

Are you getting any shiney spots or ejector marks on the case head? Sticky bolt lift is a for sure sign of over pressure. Something is changing from the new brass to the resized/fired brass. When you reduce 2 grains in a case that holds anywhere form 85 to 100+ grains of powder, 2 grains is less than 2%, which isn't much of a difference. I would tumble clean, anneal the case necks, size and trim, then see if that helps your pressure issues. If the case neck is getting work hardened from several firings, it will increase your pressure. I've seen this in my personal 300WM with some brass that had multiple reloads and had very brittle necks.
 
Re: Stiff bolt lift

Clean and lube the lug area INSIDE the rifle and your bolt.
Look for burrs etc. on the bolt lugs.
Lube the area at the back of the bolt where the FP rides the bolt.
Look for crud built up inside the bolthead extractor area.
Have you checked the cases for correct OAL?
Mic the case head dia. before and after firing.
Respectfully,
LG
 
Re: Stiff bolt lift

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Berry</div><div class="ubbcode-body"> I have noticed that after several firings there is a slight rise in the area of the neck and shoulder junction. </div></div>

This may mean you are not bumping the shoulder back when you resize as much as you think you are...
 
Re: Stiff bolt lift

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Berry</div><div class="ubbcode-body">Shoulders are getting bumped. Round chambers easily. I have this problem even with several grains less of powder. I do not clean my cases after each firing, but I do check case neck length. I turn the case necks after the first firing. I have noticed that after several firings there is a slight rise in the area of the neck and shoulder junction. </div></div>
I didn't see this reply. Your case necks need to be annealed. Most medium sized cases (308, etc) you can get by annelaing every 3-5 firings. Magnum cases need it more often, and ultra mags need it every other one, or every time. Measure your neck diameter before sizing, and then after sizing on your fired brass. See what the difference is on each cycle of brass- like once fired, twice fired, etc. This figure will change, and will give you some indication how flexible the brass is. If you size it and the case neck splits, you are well over due for annealing.
 
Re: Stiff bolt lift

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lucks</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Berry</div><div class="ubbcode-body"> I have noticed that after several firings there is a slight rise in the area of the neck and shoulder junction. </div></div>

This may mean you are not bumping the shoulder back when you resize as much as you think you are... </div></div>
The brass is "growing" from when he turned the necks.
Just curious- why are you turning the case necks? Also, what is your rifle and set-up?
 
Re: Stiff bolt lift

I am turning the case necks just once, after the first firing of the new brass. I do this so that I have better concentric necks. Some of the Remington brass has more meat on one side than the other. My rig is a .338 RUM custom Hart rifle. It is new and I am working up a good long range load. I am currently using 92 grains of H-1000 with the 300grain SMK. I started at 86 grains and have worked my way up. As far as shiny spots from the ejector hole, yes. However I can see this in all my loads from beginning load to max load. True it is more prevalent in the hotter loads. I have never annealed the necks and am thinking that you are mentioning something I should do. Any tips on doing this.
 
Re: Stiff bolt lift

0026403-11.jpg


If the brass that made hard bolt lift is cleaned and coated with Dyem, and then ran into the chamber, close the bolt, and then out, where the Dykem is scratched off is the problem.

http://www.use-enco.com/CGI/INSRIT?PMAKA=825-8310&PMPXNO=943768&PARTPG=INLMK3