bolt hard to open

[jerseymike]

what is the cause of this? I handloaded some remington brass which feeds and extracts fine, but when I shoot my Lapua brass the bolt gets stiff when the knob is pointed 2 o clock position at which time I have to give it a little slap, then I can cycle the bolt. I full length size and trim both the rem and lapua brass to the same specs. what gives?

 

[jasonk]

Re: bolt hard to open

Lapua brass may be thicker, causing a smaller case capacity in Lapua, which could cause slightly higher pressure in those loads.

 

[jerseymike]

Re: bolt hard to open

now you got me thinking, I didnt check the lapua brass to see if their were any pressure signs.

 

[MitchAlsup]

Re: bolt hard to open

Lapua brass in 308 needs about 0.3-0.4 fewer grains of powder than (say) Win cases to achieve the same operating pressures.

 

[Country]

Re: bolt hard to open

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jasonk</div><div class="ubbcode-body">Lapua brass may be thicker, causing a smaller case capacity in Lapua, which could cause slightly higher pressure in those loads.

</div></div>
+1 on that also the lapua may be a bit softer so with any extra chamber pressure it is backing up on the bolt face a bit more. Also check that the caming surfaces at the rear of the bolt are clean and slightly greased .

 

[Victor N TN]

Re: bolt hard to open

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Country [/quote</div><div class="ubbcode-body">
... Also check that the caming surfaces at the rear of the bolt are clean and slightly greased . </div></div>

+1... I was just thinking the same thing.

 

[USFTR]

Re: bolt hard to open

I had a similar problem with Winchester extracting great and Lapua (virgin included) sticking easily to the point that I was shearing off extractors if I wasn't careful. Polishing the rear of the chamber (gunsmith) solved the problem. The base of the virgin Lapua was 0.4695" and the Winchester was 0.4645". I think Federal? was also on the smaller side like Winchester. I was running very high pressures (off the scale) as well. The brass just needed a little more room to expand and contract.

 

[Fuzzball]

Re: bolt hard to open

"now you got me thinking, I didnt check the lapua brass to see if their were any pressure signs."

A sticky bolt IS a "pressure" sign. And perhaps the most reliable one at that.

 

[chefpierre]

Re: bolt hard to open

Is it time to trim the brass?

 

[9H_Cracka]

Re: bolt hard to open

If your brass weight difference is the cause then your load with the other brass is right on the edge of pressure as well.

Back your load down.

 

[Hummer]

Re: bolt hard to open

What is your FL die sizing the Lapua down to and what is dimension of your fired cases at base?