my m&p15-22 holds bolt open with empty mag
however, when i shoot to last round does not hold bolt open
is this a ammo issue?
appreciate comments what ammo you use to function last round bolt open correctly
thx
Jack

What ammo are you using?

doesn’t matter what i am using since not working,
would prefer to hear from someone with last round working and tell me the ammo they are using

Oooooookayyy......

I'm using Federal 729 bulk pack, Federal Automatch, All Aguila standard and high velocity ammo, CCI blazer, mini mags both hollow point and solid, CCI standard Velocity and Remington Golden bullet. All hold the bolt open on last round reliably.

Good luck!

thanks a bunch…need to zero down to mag or gun issue, since three mags do the same thing suspect it’s the gun
thanks
Jack

Clean and lube the bolt.

__________________
SIC SEMPER TYRANNIS

^^^^This.
My two 15-22’s eat everything I put in the magazine, mostly standard velocity 40 gr., and lock back on last round without fail. I clean and lube every 100 rounds or so including scrubbing the chamber to remove the carbon ring.

thanks to all for the replies
will give it a good cleaning and report back
Capt Jack

Could still be an ammo problem if you are using the same type of ammo in all three magazines.

Since you are being secretive about the ammo you are using, who knows? Mine runs fine on pretty much any high velocity ammo. Is this a new rifle? If so, did you clean and lubricate it before going to the range? If not new, how many rounds? Did it ever hold the bolt open on the last round fired?

I use grease on everything that slides. I began noticing cycling issues with a 22 semi-auto and wondered whether the viscosity of the grease was an issue. Switched to oil on everything in 22 and never had another problem.