Hello all...

While not new to firearms or reloading, this is my first foray into long range AR10 style rifles. I have a F&D Defense FD260 22" AR rifle in .260 Rem, which we took out today to sight in. First 6-8 rounds fired fine, then we started experiencing very light primer strikes. Disassembled rifle, firing pin is fine, hole appears fine, but when inspecting brass, the casing shows signs of very high pressure.  (see pics).

Ammunition used today was a Federal 140 gr Sierra gameking soft points

Rifle would fire fine for 2-3 rounds, then misfire with a light primer strike.

My thought was that the primer flowing back into the bolt face was causing debris to stop up the firing pin.

My question for those with more experience with factory .260 rem ammo is 1. Is this normal? and 2. Is this solely a ammo issue?

I have never seen pressure signs like this in factory loads... you can clearly see the casing has even taken on the imprint of the ejector! Bolt face picture shows metal fouling from primers/casing brass.

@LRPF52 ...

ETA:  @LRRPF52

Looking at your primers I'd say it's normal on a r700 but I'm not used to seeing that on an ar. It looks like they're using the larger style firing pin like dpms and others have used. JP came out with thier high pressure bolt with a smaller firing pin and bore just for this issue with 6.5mm and other high pressure rounds.

The ring on your bolt face isn't etched in already is it? It's hard to tell.

Isn't the f&d a piston gun? If it has an adjustment turning it down might help with the ejector marks. I'd try some 120-130gr loads if you can. Some of the 6.5 gas guns do ok with 140 and heavier but most seem to have more luck with lighter bullets. Myself included.

Everything he said above.

Biggest concern I see right off the bat is the ring on the bolt face before I even scrolled down.

I've never shot factory .260 Rem in either of my .260s. I went into it knowing that I'd only be hand-loading for a gas gun.

Also interested to know more about the rifle. I wouldn't shoot that anymore with that load.

Rifle is supposedly new.. and looking under magnification, the ring appears to be material on the surface, not etched into the surface. If it is in the surface, I take it a new bolt face is in order?

I wont be firing the factory loads anymore... I have brass and 130 Bergers on order.

Rifle is this,

F&D Defense

Jp high pressure bolt with small firing pin,adjust the piston system and maybe a slash heavy buffer. I shoot prime thru my 260 thru my larue and it shows some primer flow,most guys like the hornady eld.

Good luck
Pete

F&D rifles have unique proprietary bolts matched to the barrel, and so I can't use a JP bolt. It would be a quick fix if I could!

I assume that what I can do is start low, and find an accurate load in the 130 grain realm which doesn't show this much primer flow. Tune from there...

I'd contact f&d and see if they offer a bolt with a tighter fp hole or if maybe by chance it could interchange with the JP? My experience with the Remington I had was the primers pretty much all looked cratered, even extremely mild loads.

As much as they brag about making an amazing rifle, not using the .068 firing pin that had pretty much become the standard for 6 and 6.5 rounds. I think the normal old dpms/kac was .080 or .090. doesn't seem like much but makes a big difference.

Federal told me that they do not make any .260 ammo suitable for semi-autos.  

I shot this Superformance in the same session.

Definitely to load for it. F&D defense responded and told me that loading your own is the way to go (although, no offense to them, their manual says the opposite.. liability reasons I am sure)

My 260 shoots well with 260 prime, many others on the Larue forum say prime is too hot. It seems that hornady eld is the goto round in a 260 auto. Not quite as hot as prime and seems to group great. I’m sticking with prime as my gun shoots lights out with it and only shows light primer cratering.
If I were you I’d follow the above post and try a heavy buffer and stiffer spring along with trying to turn down the gas.

Pete

I run an LRP 07 in .260.  And yes, without the "high pressure" mitigation upgrades (HP bolt, buffer and AGB), you are likely going to continue to have issues.

If it makes you feel any better, I reload and can only use Winchester .243 brass two times before the primer pockets shit the bed.  I have all of the high pressure mitigation toys, with the exception of the HP bolt (my rifle came out before that bolt did).  The HP bolt would help, but I'm certain I would only get another 1-2 reloads out of that same brass.

As far as Federal brass goes? LOL!!! Fuck that shit.  I learned a great lesson from those guys.  I ran into a guy who had a friend who works for ATK.  He offered me 500 Federal .260 cases, which I of course purchased.  Most of them blew pockets on the first shot.  I didn't even load all of them before I threw about 200 of them in the shit can.  It made Hornady brass seem like it was made of adamantium.

Grab some .260 Prime ammo and give it a go.  I am assuming you won't blow the pockets on the first shots, but I also suspect they won't last but 1-2 loads with your current setup.

On a side note, how's the accuracy of that F&D looking?

ETA - IIRC, Hornady doesn't advise their Superformance ammo be shot out of semis.  These HP chamberings have issues enough with standard loadings and that Superformance shit is hot rodding a bit more.

FD builds these rifles purpose built for 260, and the bolt head factory fit the barrel, thus no drop in solution. I have brass and bullets, and am starting out with a H4350 around 39.5 and work up from there with 123 scenars.

Once I get an a load that gives good velocity and accuracy without the pressure signs, I will post the results. I am trying some initial loads with Berger 130s and scenar 139's as well. Fingers crossed!

If I were you I'd lean hard on f&d to get you another bolt and firing pin with the smaller diameter. .068? You're going to continue to have premature cratering until that's sorted out. After the advances in 6 and 6.5mm large pattern ar's the last several years there's no excuse to still be making them with the old .090 firing pin.

The answer is reloading. My gas guns are 2 grains less than my bolt guns.

While I agree, and have learned about about gas guns and 260 reading everything, I got the rifle 2nd hand, so there is no getting anything from the factory. Even though I got it unfired, I am not the original owner.

That is were I am at.. working up small batches in several powders and bullet weights, and create a load she likes.