AR misfires with new reloads

[AGGRO]

Ok. New upper bear creek. Shoots the old reloads great that are lead. My new loads with copper nope. I haven't spun down or up the die set. Literally one went bang out of ten I tried. I spec'd the rounds and they look exact between the ones it likes to eat and the new ones. Mixed bag brass. I'm stumped. BCG is locking up ok but no primer strike just CLICK. I brought out the caliper and it all looks exact across the two loads. I literally swapped between the two and one works fine the copper nope.

Ideas? Less than 50 rounds through the pipe.

[not-fishing]

Firing pin

Have you cleaned your bolt recently?

[AGGRO]

Firing pin

Have you cleaned your bolt recently?

It's almost new. It fires one round every time, the new ones, nope. I thought it might be excessive headspace from over sizing but it all specs out the same. I'm stumped. There was a couple with sticky ejection.

[baih777]

It's almost new. It fires one round every time, the new ones, nope. I thought it might be excessive headspace from over sizing but it all specs out the same. I'm stumped. There was a couple with sticky ejection.

what are you using to check the brass headspace ?

[AGGRO]

what are you using to check the brass headspace ?

Don't have a go/no go for 6.5. Head space is fine for my earlier loads. All of this brass was sized at the same time. The only difference is the copper projectile which, of course, makes zero sense as to why..... I'm measuring shoulder etc with calipers. I'm ordering go no go but may be a wait.

[highpower790]

With the solid copper bullet,I think it may be possible that your bolt is not fully locking.Check your oal from the ogive to cartridge base.It is my opinion that your oal is on the plus side a few thou.

[AGGRO]

With the solid copper bullet,I think it may be possible that your bolt is not fully locking.Check your oal from the ogive to cartridge base.It is my opinion that your oal is on the plus side a few thou.

This I will check. The cure? Always good info here and thanks for the responses.

[slamfire1]

I'm measuring shoulder etc with calipers.

Are you using a comparator? You cannot measure the base to shoulder of brass fired in a gas gun and determine the correct sizing length. This is because gas guns unlock while there still is residual pressure in the barrel, and cases get stretched during extraction.



This brass was all sized to 1.630, and yet after ejection from an M1a, they are all too long. These cases were coated with Johnson paste wax, which melts under the temperatures and pressures of combustion, and becomes a lubricant. This lubricant coating resulted in zero sidewall stretch during extraction. The shoulders moved forward because they were being pulled back, while there was residual pressure in the barrel. Hence the base to shoulder measurement of a fired case does not reflect chamber headspace.



You should buy one of these, in your caliber, and set the dies accordingly.



I like the view port on this cartridge headspace gage.

[tyler_sti]

Ogive of the new projectiles might be further up by different design. Check to see if there are marks on the bullet from the lands. Also leads me to think this is the issue because you said some rounds are "sticky" to eject. Typically when changing between bullets the seating die must be slightly adjusted from my experience.

[MongooseV8]

Click with no primer strike in an AR has always been cartridge preventing the bolt from fully locking ime. I agree with those above. Check your brass and bullet seating depth at ogive.

[divingin]

With the solid copper bullet,I think it may be possible that your bolt is not fully locking.Check your oal from the ogive to cartridge base.It is my opinion that your oal is on the plus side a few thou.

You're throwing out 2 different measurements there, which makes things confusing. OAL is cartridge base to tip of the bullet. Base to ogive (CBTO) is what could be causing OP's problem.

OAL length doesn't mean much other than if it will fit in the mag. The critical measurement is base-to-ogive (the distance from the base of cartridge case to the point of the bullet that engages the rifling.) CBTO is what will stop the bolt from closing. Measuring that takes a bit more fiddling to measure than slapping a pair of calipers on and seeing how long the cartridge is. You need to be able to measure to the ogive, but you also need get the corresponding measurement of the chamber/barrel. I'd suggest looking up how to measure both.

A quick test, though, to see if bolt closure is your problem without measuring, is to look at the forward part of the ejection port with the bolt closed on an empty chamber. Note where the face of the bolt is visible (should be able to see a little of the face corner.)

Chamber one of your reloads. Check to see if the bolt is as far forward as it was on the empty chamber. If it is, the problem is likely not seating depth. If it isn't (i.e. if the face of the bolt is further back) then it could be that the bullet is engaging the rifling prior to the case fully seating in the chamber (could also be the amount of sizing the case is getting, among a few other things.) Seat the bullet a bit deeper (a bit more than the difference in bolt position) and see if it chambers and allows the bolt to close. If it does, that was your problem. If it doesn't, I'd start looking at case sizing.

On a bolt gun, the same test can be done using bolt closure resistance as a guide (assuming the bolt closes.)