My normally super-reliable Bushmaster jammed every other round with new Federal 69gr Match Kings. This is my first time shooting them.

I nornally use various brand 55gr bullets without a hitch...What's going on here?

I know that the 69gr bullets are longer than the 55's and there is not much space between the tip and the front of the magazine, but the 69's should feed, right??

I am using good Colt mags, so I can't figure it out.

Any opinions??

They should still be under the oal needed for a mag. Try another mag or clean the chamber?

I set my bullets to about 1/16th of an inch from the mag wall. Maybe the ogive is not conducive to autoloading. A 69-grain bullet is going to have a longer, slower curvature than a 55-grainer. That might be the difference. I also tried to load 75-grain Hornady's once. The ogive is so long the bearing surface was inside the case mouth. The bullet was not held tightly enough to make the damned thing stick in it-- they just fell inside and I never tried them again...

You say "new ammo," but you only make reference to the bullet. Are these suspect rounds commercial or reloads? I am in the process of screening out loaded rounds that I resized just a red hair or two too long to chamber. I procured a case comparator to do this. I'm finding that even 5 or 6 thou will prevent chambering and lock-up. I'll have to split them open, resize and reload. What a pain in the obama. But it must be done...

Hi Fellas,

They are brand-new Federal Factory 69gr Match Kings.

They should be OK right?

Is this ths same rifle you recently changed to a flat-top configuration? Was it working fine afterwards?

When you say it is jamming, is it failing to feed, failing to eject, or what exactly?

Thanks Charles, you are sharp! Yes it is the same rifle and converted to flat top by buying the new upper...not barrel just the reciever part....never thought of that, thanks!
With that in mind now, I put approx. 100 rounds of 55's through it without a problem, but the problem with the 69gr was that the bolt would push the round foreward, but the bullet itself would stay pointed downwards against the front of the magazine and be jammed against it. If I pulled back on the bolt again and let it go it would chamber and fire the round. A few of the live rounds that I ejected, I noticed that the bullet was pushed back into the case, with only the tip sticking out.

If they stay pointed down in the magazine you mught try a different mag.

I am no AR expert so I can't say if it is a feed ramp, chamber, or mag issue (spring or follower).

Will they chamber with the forward assist, or does that just drive them against the front of the magazine?

Thanks Charles, and I'm no AR expert either.

The foreward assist didn't help.

I tried a few different brands of magazines with the same results.

I think my solution is to stick with the 55's!

quote:

I put approx. 100 rounds of 55's through it without a problem, but the problem with the 69gr was that the bolt would push the round foreward, but the bullet itself would stay pointed downwards against the front of the magazine and be jammed against it. If I pulled back on the bolt again and let it go it would chamber and fire the round

Leopardtrack, that's a MAGAZINE/MAGAZINE FOLLOWER problem.

Two questions......

What type of magazine are you using? Manufacture? Capacity?

And ..... when you are loading the Fed. MK 69s are you pushing each round back to make contact with the rear of the magazine as you insert each round?

The Fed Match ammo shouldn't be the problem unless the OAL is over 2.260".

Hi DaMan,

I used a few diff brands of mags, and I am wondering now if I pushed them to the rear or just snapped them in. One thing I do know is that I didn't load them any differently than the 55's.

BTW dosen't the recoil knock them around in the magazine anyway?

Sounds to me like they are to long for the mag or that they are not causing the bolt to travel far enough back to the cycle bolt properly. Then the bolt will not have enough power to strip them out of the mag.

I was out shooting with a buddy and all of a sudden his very reliable AR started to have the same trouble with 55gr factory fmjs. I though heck it just got dirty. So we put it away when we got back home cleaned and oiled to same trouble.

So I did a complete Armorer inspection on it. What I found was the front sight gas block had loosen up and not allowing enough gas to get back and work the action.

Tighten it back up ran 20 mag through it as fast as I could pull the trigger. He took it back to the place that put the sight gas block on it to have them fix it.

quote:

Originally posted by Leopardtrack:
I used a few diff brands of mags

This doesn't tell me a whole lot. Military (black,green, brown, metal or synthetic follower) or an aftermarket magazine?

quote:

Originally posted by Leopardtrack:
.... and I am wondering now if I pushed them to the rear or just snapped them in. One thing I do know is that I didn't load them any differently than the 55's.

The White Box 55 gr. ammo is very short (2.240" or shorter). So it's not as critical to make sure these rounds are fully to the rear.

I'm assuming that the bolt caught the problem round properly behind the rim and then pushed them forward and down with the tip of the bullet stopping on the front of the magazine body. This is a follower or OAL or proper loading problem.

If you think it is a magazine follower problem, you might want to replace the magazine followers with the newer anti-tip green followers (available from Brownells). They will fit all military type mags.

The US military is even issuing a better sand color follower...... but it won't be available for a while on the civilian market.

quote:

Originally posted by Leopardtrack: BTW dosen't the recoil knock them around in the magazine anyway?

No.

'track, here's something you might try: Rock the magazine to raise the tips of the bullets, then fold up a small piece of copy paper such that you can slide it between the rear of the magazine and the well. It will cause the magazine to tip upward, aiding in getting the bullet tips into the feed ramp. Once you've shot away all those funky bullets, seek alternate solutions...

Thanks to you all for your effort...I think that I am just going to stick with the 55's.

Thanks!

Frank

I've seen thousands of rounds of Federal 69gr match ammo fired in several brands/styles of AR15 rifles. It normally seemed to be pretty reliable stuff.

If the round isn't making it out of the magazine then I'd agree with DaMan. You didn't say which magazines you used and some are better than others. The original 20 rounders are usually very reliable, the thirty rounders need help. The green follower is usually a good fix. I've just gone to using Magpul magazines, they always work.

quote:

Originally posted by Rick R:
I've seen thousands of rounds of Federal 69gr match ammo fired in several brands/styles of AR15 rifles. It normally seemed to be pretty reliable stuff.

It's pretty much the magazine length factory load favorite of the AR-15 High Power crowd.

Frank, I would recommend lighter bullets in your 1/9" twist 16" flat top, but not because I'd suspect feeding problems with the 69gr Federal Match cartridge.

My 20" HB accuracy rifle is 1:9 and it does very well with 69 gr Fed Match ammo.

I usually feed it with 20 rnd mags but the C Product 30s with green followers and (expensive) H&K 416 mags work well too.

Hey DaMan,

Sorry for the delayed response!

Just wondering why (besides twist) do you recommend the lighter bullets for me?

quote:

Originally posted by DaMan:

quote:

Originally posted by Rick R:
I've seen thousands of rounds of Federal 69gr match ammo fired in several brands/styles of AR15 rifles. It normally seemed to be pretty reliable stuff.

It's pretty much the magazine length factory load favorite of the AR-15 High Power crowd.

Frank, I would recommend lighter bullets in your 1/9" twist 16" flat top, but not because I'd suspect feeding problems with the 69gr Federal Match cartridge.

quote:

Originally posted by DaMan:

It's pretty much the magazine length factory load favorite of the AR-15 High Power crowd.

Frank, I would recommend lighter bullets in your 1/9" twist 16" flat top, but not because I'd suspect feeding problems with the 69gr Federal Match cartridge.

quote:

Originally posted by Leopardtrack:
Hey DaMan,

Sorry for the delayed response!

Just wondering why (besides twist) do you recommend the lighter bullets for me?

I think you would be better served with an accurate (and lighter/faster) heavier jacketed hunting bullet. Like the Nosler 60 gr. partition.

The light jacketed 69gr. Match is designed for paper punching from longer barrels.

Check out the Federal line of ammunition. The P223Q is recommended for medium game where legal.

You are "DaMan" thanks!!

No problem!

BTW - Federal P223S loaded with the Barnes Triple-Shock X Bullet would also be another good candidate.

Winchester's 64gr Power Point load (RA223R2) works well from a carbine length barrel and if you can find it the price isn't too bad.

If you are running a new upper, be sure to keep the bolt wet with lube, or it is going to jam more often than not.

Check the overall length of the cartridges. They should not exceed 2.260". Some people will load them to 2.26", but 2.260" is max length and it doesn't take more than a few thou over this to cause magazine jams.
Remember, the OAL of the bullets can vary by more than .010".

I prefer them to be seated to 2.25" for the sake of reliability.

quote:

Originally posted by Rick R:
Winchester's 64gr Power Point load (RA223R2) works well from a carbine length barrel and if you can find it the price isn't too bad.

The 64gr. Win. has been a longtime favorite of those who shoot medium game with the .223. Reasonably priced too.

Today I bought some 60gr. Nosler Partitions to replenish my dwindling supply.

$23 for a box of 50! That's a lot more than they cost a couple of years ago. But the larger box makes it worth the price increase because it looks like you're getting more bullets!

New box left...... old box right.

Sure sounds like a magazine problem. C-Producsts have had some rough ones out there when they first got up and running. Since they moved to CT their reliability increased a ton.

I really like the Magpuls. If you are running mags other than (Colts, LaBelle, H&K, O-Kay Industries, Magpul) I would seriuosly consider changing the follower to a Magpul.

What feedramps are you using?

Any changes to the lower? It is possible that the magazine catch is would in a bit to tight. Happened to one of our guys rifles and took me forever to find that issue (Thanks John Noveske!!).

I also agree that 69gr SMK are for paper only. 1/9 should be fine with them. I use the 60gr Partition and 60gr BT all the time. So far haven't met an AR that does not like em.