6.5 WSSM Bolt Lift Problems???

[J. Pendergraft]

Joel,

Thank you for that info. I have order some new brass to eliminate a bad batch of brass. I was planning on pushing it a little harder when I get the new brass. So what your saying about the bolt thrust is:that the case is not blowing out to the case walls as quick as the shoulder are blowing out to the front of the chamber. Thus running it at higher pressure will reverse this process. The only concern I have is; I have run this case hot to about 3050 fps and started seeing shinny spots on the back of the case from the ejector hole, with an even harder bolt lift, so I backed it back down to 2950. Please keep the ideas coming.

Thanks again, Charles

If you have already run the pressure up then I'm inclined to believe you have a fit problem which is what others have already mentioned. Nat's suggestion to enlarge the rear portion of the chamber a bit will likely cure that problem. I'm a believer that the chamber needs to measure .002-.003" larger than virgin brass to avoid case sticking issues.

 

[C. Ballard]

Problem solved

Thanks for all the info. After annealing the #$%! out of the cases the bolt lift is normal. Again thanks for all the help.

Charles

 

[RoyB]

I'm well aware that this thread is over a year old. But I just built a 243 WSSM on a Savage Large Shank action (was a 270 WSM) with a 1-10 Twist Kreiger barrel. I'm having VERY hard bolt lift on mild loads, and as I increase the charge, the bolt lift gets easier. I also experience lots of black gas blow by around the neck and shoulder on mild loaded cartridges.

Is there anything new to report since this thread started?

 

[LivetoHunt2008]

are you turning your necks down?

if not..you should consider. I turned my necks down to 0.0165"...no more gas blowback...

...and as others have previously said...I bump the shoulder back and I anneal as well...

 

[Lynn]

I'm having VERY hard bolt lift on mild loads, and as I increase the charge, the bolt lift gets easier. I also experience lots of black gas blow by around the neck and shoulder on mild loaded cartridges.

If your not hitting your new brass hard enough with those real thick cases it never really fireforms to your chamber properly and thats why your stiffer loads eject better.The stiffer loads are doing a better job of fitting the brass to your new chamber.
The black necks are as everyone has already posted because of the extra thick necks not bouncing back thus allowing the gas to flow around them.
My 50 BMG has the same neck thickness as my 243 WSSM does.
On my Mach V a 3900 fps load won't create enough pressure to fireform my cases fully.
Waterboy

 

[Tod Soeby]

I was working on my 6.5WSSM this summer and tried to rechamber a fired round.....could hardly close the bolt. 48 gr H4831 / 140 VLD at about 2940. I did notice a slight bolt lift issue, but I had fired hundreds of rounds with this load. I panicked!!!!! Went down to the 45.5 grain node....same thing.......again...panic. Went down to 43.5 @ around 2600.....SAME THING. Bolt opend a tad sticky, but it was almost a chore to rechamber a fired case....lots of grinding feel comming from the bolt lugs.

I am convinced it is a "spring back issue" with the brass, as I had been up to 51 Gr H4831 W/O any other PSI signs except the slightly sticky bolt. So, I am done with the "panic attacks" (at least with this BBL)!!

I did anneal my brass once, but it was my first crack at it.....I don't even know if i did any good.....or HARM!! Oh Oh....I feel another panic attack comming on!!!