Ive got a new mcx looks and acts fine when empty but when a cartridge is added to the equation the bolt does not close all the way. It looks like the extractor is hitting on the rim of the cartridge rim and stopping the bolt from fully closing.
Anyone else have a similar problem?

Sounds like you're gently easing the bolt forward instead of letting it slam forward with the recoil springs power. Are you feeding from the mag or are you putting the round in the chamber with your fingers and then easing the bolt forward? If you are easing the bolt forward then there is a good chance that the extractor will not slip over the rim. Another question:::: Have you actually fired this thing and does it extract during firing? Also are you using the right caliber ammunition that your MCX is chambered in?

Can we assume it’s factory ammo? Not reloads? Yes, with a semi-auto standard procedure is to allow the bolt to strip a round from the magazine, full force to load. No ‘riding’ the bolt forward at reduced force.

Ok, i do not ease the bolt forward. Never have.
The force of the action is actually shearing off a fair amount of brass from the cartridge rim from ramming into the extractor.
I have field striped the cbg down to the extractor and it does not seem to rock at all.
The spring has a o-ring around it which I presume
Is correct so im at a loss.

Link to photo of brass

I'm no expert and it's only one photo but it seems as if there are a lot of "scratches and scritches" on the sides of that case. Makes me wonder what chamber looks like. I'd also be interested in checking headspace.
Best wishes, mike

quote:

Originally posted by sq4570:
I have field striped the cbg down to the extractor and it does not seem to rock at all.
The spring has a o-ring around it which I presume
Is correct so im at a loss.

Sounds like the o-ring maybe too thick, spring maybe too long/too heavy or the extractor and or extractor recess not milled right if it is not pivoting. If thats the case I would contact Sig for a repair or replacement.

quote:

Originally posted by mike28w:
I'm no expert and it's only one photo but it seems as if there are a lot of "scratches and scritches" on the sides of that case. Makes me wonder what chamber looks like. I'd also be interested in checking headspace.
Best wishes, mike

Can you insert the round (completely) by hand and then have it fall out by tipping the gun muzzle up ??

Howdy 45-70 !!

Any update on your AR ?? I always learn from these types of issues !! Thanks !!