I have a MKIV 22/45 that installed the Volquartsen competition bolt in along with their Accurizing kit. I put 500 rounds through it before replacing any parts and never had a problem with a variety of ammo. After installing the parts I can't even get through a mag without anywhere from 4-8 FTF. There is either no mark on the rim or a light strike. I have pulled the bolt back out and put the original back in and burned through 200 rounds without a problem. Everything on the VQ bolt looks nice, I pulled the firing pin and no visible damage or burs. Any ideas what to look for next?

Have you asked Volquartsen if they have any clues? They might know what is wrong. Who knows, they might make it right.

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The best I can with what I got

They may still be open today.
Call them.

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i actually just got off the phone with them, they said it sounds like the firing pin return spring may not be strong enough to push the firing pin full rearward so it's not getting enough inertia to reliably set off the next round. They're sending me a new firing pin spring.

There ya go.....

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SIC SEMPER TYRANNIS

I just went through this with a Ruger MKIII. I was getting misfires. A basic cleaning didn't fix it, so I tore down the bolt. I was prepared to tear down the lower assembly too, but didn't need to. The firing pin rebound spring came out in two pieces. I couldn't find it on Ruger's website and didn't want to pay the price/shipping from Numrich. I sent Ruger an inquiry and they mailed me the part. Voila! Problem solved.

I had the same thing happen recently to a MKII that I bought new in 1982. Spring broke after only about 1.4 quadzillion rounds. I called Ruger and a new spring showed up in the mail 3 days later at no charge and that fixed it right up.

Attached Images

Ruger MkII 0019.jpg (119.8 KB, 43 views)

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Interesting! It looks like yours broke in the same place as mine did. If I still had the pieces I'd count the coils to verify. I don't think I had a quadzillion rounds through mine. Most likely just a trizillion!

I pulled the factory bolt apart as well as the VQ bolt just to try and compare things. I found the spring in the factory bolt was quite a bit stiffer. I put it in the VQ bolt with their heavier firing pin and it’s ran a couple hundred rounds without issue. We’ll see what the spring they send me feels like. I may keep the factory spring behind the firing pin.