This is a real and honest concern. I fear it will only be answered in time.
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Interesting. That runs contrary to what others on this forum have experienced:
https://www.m4carbine.net/showthread...question/page2
https://www.m4carbine.net/showthread...essed-SBR-Ever
Perhaps this is on a case by case basis?
When I have the chance, I will test my LMT Enhanced carrier against a standard Colt carrier on a 20" barrel with an SLR adjustable gas block and report the results here.
I have about 2,000 rounds on the rifle described in post #227 of this thread and 16,000 rounds on an Adams Arms piston gun with 0.4" of extended travel and have had no issues with breaking the bolt catch on either gun. Springs are Tubb AR-15 flat wires. Granted, the competition gun has esssentially no buffer weight and the piston gun is using Bill Alexander's Enidine hydraulic buffer which moderates the impact of its mass on forward travel so results may be different with a standard H2 or H3 buffer.
That spring doesn't hurt either vs a round extra power spring. On a side note, I am fond of the flat recoil spring characteristics in ARs.
I love Tubb's flat wire springs. There is a much less pronounced increase in resistance throughout the deflection range of the spring. Since the force of Tubb's spring in the closed bolt position is identical to a Springco blue spring but is 2 lbs, lighter in the open bolt position, you are right in that it helps with unduly battering the bolt catch.
Tubb goes into specific numbers in this video: https://www.youtube.com/watch?v=8fMVZbrnvu8
The important thing to note is that the 36 coil flat wire has the same weight in the closed bolt position (10.5 lbs) as a Sprinco Red while being slightly lighter than a standard AR spring in the open bolt position (16.3 vs. 16.7 lbs). In contrast, the Sprinco Red weighs in at 18.4 lbs. with the bolt open.
Granted, this is in a rifle length receiver extension but I'm pretty certain the benefits are still there in a carbine tube.
InRangeTV just did a video on it.
Nothing we don't already already know, but the footage is pretty good quality.
https://youtu.be/Rs1kb5IBceE
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Bill G. says they are working on a new AR offering partnering with SureFire. I suspect they are going to be making a carbine based on the OBC. Watch this video https://www.youtube.com/watch?v=cOXAwFdqsv0
Mig1nc,
That video is very interesting, and I bet (read: pure speculation) that they incorporated a longer cam-pathway and slightly different geometry from the OBC into their BCGs to get the performance that they are claiming. Looking at the bolt in the video, it seems to be standard length as well. Geissele is doing some really, really cool things, and it's getting more difficult for me to justify most other manufacturers' offerings if they are comparable to a Geissele product.
I'm eyeing up an OBC to refresh an SPR build (largely just "because") which is running an H2 and a carbine-length tube at the moment. The rifle functions wonderfully at the moment, but I'll be curious to see how the OBC affects follow-up shots at distance.
We are living in a really cool time for subtle innovations on the AR platform.