[gunner69]

Yesterday I was told to stay AWAY from Hornady Ammo. It IS Not to the original Rem specifications. Hornady is using a different "longer throat" on their ammo. A good friend has an AR-15 in 6.8 SPG, and has been having problems. Ty, if you see this post you may want to check out some Hornady ammo to see if there will be a problem in the XCR. I plan to use only Remington brass which has the large rifle primers. Silver State brass uses small rifle primers. Mix your brass and you are headed for disaster. I am using Remington 115gr bullets (both FMJ and SP), with 23.5 gr of H4198, Federal Gold Match primers. When I get my barrel kit for the XCR I will pass on the results of this load. My info off LoadData gives the same 23.5gr for IMR 4198. Have a great shooting day. Jack

 

[DSM]

It wouldn't surprise me but to manufacture/sell a round I would think they would need to comply with SAAMI specs. Throat length is something dealing more with the barrel and the difference in custom chambers and factory chambers can be fairly substantial sometimes.

6.8 is a pretty BA cartridge though, a lot of punch. Unfortunately I don't think its future as the new service cartridge in the military is going to happen, not in the near or intermediate future anyways. Folks can say "bolt, barrel, magazine is all you need" but thinking that Uncle Sugar has hundreds of thousands of perfectly fine functioning 5.56 rifles sitting around, well, the math doesn't add up. Yeah, yeah, gov't wastes more money buying paperclips for congress but the 5.56 is the legacy cartridge. In my humble opinion, we'll see every last ounce of life squeezed from the M16/M4 platforms before anything major happens. Look for the basic cartridge to upgrade first. The Mk262 rounds are getting more and more common downrange. While producing the amount of Matchkings to load up DoD stocks would be 'spensive, developing a heavier, say 70-75gr FMJ, wouldn't. The capability of the round is increased and all without ever changing every bolt, barrel and magazine. The 1/7 twist will spin bullets slightly past 80gr. So why I like to shoot my 6.8, admittedly in an AR platform at the moment, 5.56 still has a lot of life left in it for the tiem being.

 

[kolob]

Now you guys will understand why we waited a while to get into the 6.8s. Here's the history of the problem with 6.8. Remington rushed to get the spec. to SAAMI. The problem was that the throat was too short. With the throat short as the bullet leaves the case, it encounters the rifling too quickly resulting in a pressure spike. This pressure spike has blown up many an AR-15 in 6.8.

What Remington did was load its rounds down. This resulted in lower performance for the round (less velocity and energy on target). Other manufacturers didn't load their ammo down.

So what we did was put sufficient lead in our chambers. Yes, you can shoot all the ammo: Silver State, Remington, and Hornaday. In other words we did it right. The only way we do things.

You should also know that the XCR has a better bolt and extractor than the AR-15 guns. We've designed this so that even if there is an overpressure situation, you're not likely to blow up your gun. In fact, we pushed projectiles half way down the barrel and shot another round through it. No explosion but the barrel does get ringed. DO NOT TRY THIS AT HOME OR WITH ANY RIFLE, ESPECIALLY NOT YOUR AR15. YOU'LL BLOW IT UP AND MAY GET HURT IN THE PROCESS.

There's a lot more design advantages to the XCR that are deep under the skin. You cannot get these advantages with any gun based on the Stoner bolt. That's why we're not using it.

Sincerely,

Alex J. Robinson
Manager
Robinson Armament Co.

 

[bolster]

Now you guys will understand why we waited a while to get into the 6.8s. Here's the history of the problem with 6.8. Remington rushed to get the spec. to SAAMI. The problem was that the throat was too short. With the throat short as the bullet leaves the case, it encounters the rifling too quickly resulting in a pressure spike. This pressure spike has blown up many an AR-15 in 6.8.

What Remington did was load its rounds down. This resulted in lower performance for the round (less velocity and energy on target). Other manufacturers didn't load their ammo down.

So what we did was put sufficient lead in our chambers. Yes, you can shoot all the ammo: Silver State, Remington, and Hornaday. In other words we did it right. The only way we do things.

You should also know that the XCR has a better bolt and extractor than the AR-15 guns. We've designed this so that even if there is an overpressure situation, you're not likely to blow up your gun. In fact, we pushed projectiles half way down the barrel and shot another round through it. No explosion but the barrel does get ringed. DO NOT TRY THIS AT HOME OR WITH ANY RIFLE, ESPECIALLY NOT YOUR AR15. YOU'LL BLOW IT UP AND MAY GET HURT IN THE PROCESS.

There's a lot more design advantages to the XCR that are deep under the skin. You cannot get these advantages with any gun based on the Stoner bolt. That's why we're not using it.

Sincerely,

Alex J. Robinson
Manager
Robinson Armament Co.

This ^ is why I'm buying an XCR in 6.8. My 5.56 XCR has been a great gun too.