Long stroke SureFire Carrier

[Spart]

It looks like Surefire might be finally bringing this to market. Lumped in with a bunch of new flashlight designs, it got mentioned in this article:

http://www.thefirearmblog.com/blog/2...ire-spotlight/

No word on pricing. The design has changed subtly from when it was shown last. I am a bit disappointed to see that they're still going with a modified carrier key. DPMS (I know...) also overcame the clearance issue in their 308 GII guns, and they used an integral tombstone (like some piston carrier designs) with a pinned-on spigot. Savage is using (or has licensed) the same design for their new 308/6.5CM rifles. Seems like it could be used to good effect with this. I'm sure they've done their due diligence testing the reliability of the modified key, though.

Here's the most relevant blurb:

[Grip]

didn't read through 10 pages of this thread, but there is a good detailed video on youtube with this surefire BCG from shot show 2018.

Just figured some of you may want to see it. They talk about the larger single gas key screw too.

[BufordTJustice]

It looks like Surefire might be finally bringing this to market. Lumped in with a bunch of new flashlight designs, it got mentioned in this article:

http://www.thefirearmblog.com/blog/2...ire-spotlight/

No word on pricing. The design has changed subtly from when it was shown last. I am a bit disappointed to see that they're still going with a modified carrier key. DPMS (I know...) also overcame the clearance issue in their 308 GII guns, and they used an integral tombstone (like some piston carrier designs) with a pinned-on spigot. Savage is using (or has licensed) the same design for their new 308/6.5CM rifles. Seems like it could be used to good effect with this. I'm sure they've done their due diligence testing the reliability of the modified key, though.

Here's the most relevant blurb:

"Improved cam path allows the chamber pressure to drop another 15% before unlocking which permits more gasses to exit the bore"

"Invented by the legendary Jim Sullivan, the designer of the M16, the SureFire Optimized Bolt Carrier (OBC) improves functioning of the weapon system during both unsuppressed and suppressed ring. The patented design makes numerous improvements to the standard Mil- Spec full-auto bolt carrier group by allowing more time for reliable feeding of ammunition from the magazine, while nearly eliminating bolt-over-base malfunctions. The OBC also delays unlocking of the bolt during the ring sequence, which allows expanding gases more time to exit the bore, in turn reducing back-pressure. Additionally, the neutrally balanced counterweight improves carrier and barrel extension lock-up, and eliminates bolt bounce."

Would LOVE to see how much reduction the LMT enhanced carrier provides compared to the 15% reduction in chamber pressure of the SureFire carrier "system". I call it a system because it uses proprietary buffer and spring. But, if it does what I think it can do, I likely won't give a shit about that. The SF carrier provides what no other std length carrier can: AKM pattern bolt-overrun of the round stack/magazine/bolt catch when fully out of battery.

THAT is arguably one of the largest contributors to the AKM pattern rifles' air of "ultimate reliability".....that and the fact that anything not made by Jim Fuller is overgassed like a MFer.

[BufordTJustice]

didn't read through 10 pages of this thread, but there is a good detailed video on youtube with this surefire BCG from shot show 2018.

Just figured some of you may want to see it. They talk about the larger single gas key screw too.

link?

EDIT: Nevermind.

14:00 in the video:
https://www.youtube.com/watch?v=OrqHv0gHzCs

DOUBLE EDIT:

* MSRP $399 for the entire system.
* Uses an H2 "s" (ostensibly for short) buffer at 5oz
* Uses proprietary buffer spring
* Uses an as-yet undisclosed coating on the BCG and Bolt with highly lubricious and excellent anti-wear properties
* Uses a bolt with a captured extractor hinge pin (as seen in the video, but unmentioned)

It appears to me that the altered cam-pin path offers quite a bit of additional forward bolt travel even than the LMT enhanced carrier.

Also, who doesn't love Jim Sullivan???

[Spart]

didn't read through 10 pages of this thread, but there is a good detailed video on youtube with this surefire BCG from shot show 2018.

Just figured some of you may want to see it. They talk about the larger single gas key screw too.

Not sure if this is the same video, but discussion of the OBC starts at 14:05: https://www.youtube.com/watch?v=OrqHv0gHzCs

A few extra details from there:

MSRP $399
5oz buffer
Not specifying the coating, but it doesn't look to be phosphate. Earlier version show of this appeared to be NiB or similar, this looks kiiiinda nitrided?
Available end of Q1 (heh)

[ODgreenpizza]

Looks like you get the benefits of running an LMT E carrier and LARB buffer in one unit but maybe better. I suspect the long delay before release was for surefire to come up with a spring design that would survive more than a couple thousand rounds. I'm definitely interested.

[Spart]

Looks like you get the benefits of running an LMT E carrier and LARB buffer in one unit but maybe better.

The overstroke setup is something that's not offered anywhere else. This is the summation of a few design improvements.

If you haven't given Jim Sullivan's patent a once-over, it's quite enlightening: http://www.freepatentsonline.com/9038525.pdf

[Biggy]

Apparently these are getting closer to becoming a reality. As mentioned above the Surefire rep said these *should* be available at the end of Q1, I guess we will see on that. IMHO, while not low in cost, I could easily justify it for it increasing the AR's reliability and probably the bolts longevity. Below is a link to Surefire at 2018 SHOT SHOW. Info on the Surefire OBC starts at 14:06 in the vid. The only thing that could possibly make the Surefire OBS long stroke system any better if the compatibility is there, would be at some point adding geiselle's new bolt made out of carpenter 158 plus steel and their cobalt cam pin. The OBS LS system should be especially beneficial and work well with the new high pressure M855A1 ammo.

https://www.youtube.com/watch?v=OrqHv0gHzCs (2018 SHOT SHOW)

https://www.youtube.com/watch?v=L8JWUvt65eo (older vid on the OBC)

[Spart]

The only thing that could possibly make the Surefire OBS long stroke system any better if the compatibility is there, would be at some point adding geiselle's new bolt made out of carpenter 158 plus steel and their cobalt cam pin. The OBS LS system should be especially beneficial and work well with the new high pressure M855A1 ammo.

Regarding the compatibility, doubtful. As mentioned before, the Surefire bolt must have some sort of captive extractor pin, since on a normal AR the carrier is what keeps that pin captive. In this design, the bolt sticks out too far from the carrier for that to work.

I agree about probably working very well with M855A1. I hope the Army takes a hard look at this.

I'm not so sure that "wouldn't it be great if this was combined with X bolt improvement" is a good way to think about this design. Like people earlier in the thread that mentioned it would be nice to combine this with the KAC enhanced bolt. Yeah, maybe. But both designs are mitigating the same thing. This system is supposed to unlock later, which on it's own is going to make the bolt more reliable. Stacking extra tech on that might be putting it past a point of diminishing returns - the bolt just needs to outlast the barrel. When you replace the barrel, you need to replace the bolt anyway.

[1168]

Maybe this is a dumb question, but will the long travel cause bolt catch problems? I’m thinking about 9mm ar’s needing a spacer or longer buffer to prevent that.