I have a new Cavalry Arms CAV-15 with about 2-300 rounds through it.  Since I bought it, the bolt will not catch and stay open after the last round has been fired from a magazine.  I tried all different magazines and ammo, but no success.  If you pull the charging handle back with an empty magazine in, then the bolt will catch and stay open.  My theory is then the spring inside the stock is too stiff and is preventing the bolt from staying open, but is light enough to allow the action to cycle through with no problems.  Is there a way to lighten the spring?  Or does it need to be fired another 500 times to break the spring in?  Thanks...

I take it that this rifle was purchased as a whole rifle, not assembled yourself?

The spring inside the stock has "nothing" to do w/ it not holding open.  Odds are it is 1) the magazine spring 2) The spring that for the hold open.

The magazine spring maybe too weak to push up on the hold open.  New spring should clear this up.  The spring inside the hold open maybe too "stiff".... usually this and the weak mag springs causes the last round hold open not to work.

The instructions that the stripped CAV-15 lowers come with cover the weak mag spring issue.  It states that the spring for the bolt hold open should be trimmed a few coils to work with weak mags.

Personally, I don't mind if it holds open or not.  But that is me.  I have a few CAV-15 rifles and a bunch of mags.  As long as it feeds and fires, I don't worry about the hold open.  Maybe a little lube onthe catch will make it move more or over time it will "wear in".

Sorry if I wasn't much help.

The previous thread assumes that the carrier is driven hard enough to take it all of the way back... Then the mag spring has to push the catch up more than the return spring wants to bring it down, and it has to do it hard enough that the catch locks before the carrier is past the catch. If either the catch or the spring are binding, the catch may not won't work fast enough to grab the carrier.

Another possibility is that the gun is short stroking (short recoil in the TM). Many sources:
Front sight housing gas hole not aligned with port in barrel; machining chips in sight housing; carrier key screws not tight (and staked); excess drag on action from bent buffer spring, large carrier, tight upper, hammer, etc; rough chamber, and many more. If making certain that the catch is working properly does not fix it, check back through here. There are a bunch of threads that cover the topic.

Thanks for the information.  I went and put some oil on the bolt catch as it was a little stiff to move.  It was loose enough that I thought it should be working, and if you pull the charging handle back with an empty magazine, the bolt will catch.  Maybe there is a combination of things that will work themselves out over time?  Guess I'll have to go shooting... :)  Thanks for your help...

I handled a guys new built up cavarms this weekend and noticed a couple of things: there was some binding when pulling back the charging handle to the point that you could release it when it started to bind and it would hold the bolt and the hold open had such a tenous hold that when i set it with no mag and gently set the rifle down on its left side the bolt went home.  BTW he said he had clipped some springs so he may have done the mod cararms suggests.

So from this sample of one i concluded that there was some cleanup to be done in what passes for the extension tube and that there was something out of whack with the BHO machining in the rcvr.  DANG it was a light rifle tho with a gov profile 20" barrel.

It is an easy fix.  The spring in the mag catch need to be trimmed a little.  Take out the pin for the mag catch and cut a coil or two off and reinstall.  If you have any question call or email the staff at CavArms.

480-833-9685
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