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I’ve got a Knight’s SR-15 Mod 2 with the dual ejector 3.2 bolt.
It is 100% reliable. Just like all of my AR’s with single ejectors.
No experience with KAK. I know nothing about them.
I would be more concerned with having a bolt made with the correct materials and processes from a quality manufacturer than the number of ejectors that it has.
I have used bolts from LMT, Colt, FN, SOLGW and DD.
None have failed me.
It is 100% reliable. Just like all of my AR’s with single ejectors.
No experience with KAK. I know nothing about them.
I would be more concerned with having a bolt made with the correct materials and processes from a quality manufacturer than the number of ejectors that it has.
I have used bolts from LMT, Colt, FN, SOLGW and DD.
None have failed me.
Biggest appeal with dual ejectors is probably longer spring life and lengthened spring replacement schedules, along with more consistent ejection pattern.
But as said so far, the single ejector just works, and has done so since 1957.
But as said so far, the single ejector just works, and has done so since 1957.
I get that and I have a few spare BCMs. And am currently using one.
What I’ve noticed about the dual extractors that my Seekins SP10 has is that it is so easy on the brass. And I’m wondering if similar phenomena will apply to the AR15 platform.
What is the normal replacement schedule?
I'm seeing between 3-5k online for non chrome silicone
The problem is brass preservation. I was hoping the dual ejectors would aid in that endeavor.
Ahhh.. now I see your context for the question.
Are you speaking of a specific issue ?
Like extractor smear ?
I would bet your gas system length, chamber and gas port size would be a factor to consider as well.
Big dents from ejection? If so, you could remove the ejector and trim the spring. Personally, I’d rather have the 100% reliable ejection but I’m risk averse
I just change the bolt every two barrels. It’s $40. Old one goes in one of my kit bags in case of a field failure.
OK, wtf is KAK?? I see this floated around here and there. Enlighten me.
On edit: OK, I see who they are, but how come I never see them mentioned except in obscure forum posts? Never see their products for sale from any popular vendors?
On edit: OK, I see who they are, but how come I never see them mentioned except in obscure forum posts? Never see their products for sale from any popular vendors?
Depends on how compressed the shoot schedule is.
If you’re burning down 500rds per day, week-after-week, you would lean to 3k, but barrels will be toast pretty fast as well. Guys in The Unit cited barrel replacement every 2 weeks for 723, 727, and M4A1. Lighter barrels will shoot out faster.
This is all assuming actual Mil-Std springs, not civilian market imitation trash imported from Asia, or sourced from some other vendor who doesn’t give a rip about or even know the the TDP call-outs.
If it only takes 6 months to burn through 5000rds, then you can replace the ejector spring at that time.
One thing most might not know is that every TDP AR-15/M4 has a spare ejector spring right under your fingers.
Your selector detent spring housed in the pistol grip is also an ejector spring/same part in the TDP.
I have 3 bolt disassembly tools, 1 dedicated AR-15 and the combo AR-15/AR-10 tools from Brownell’s.
Makes bolt disassembly very easy.
Knights are doing it for added backpressure from high backpressure cans, and also, in testing, it extends the reliability of a dry dirty gun.
They are doing it to add back pressure?
No, to get rid of the bass when you speed up the system with a high back pressure can
they are actually quite popular
I go longer and carry a spare at all times.
FWIW, I believe KAK supplies parts to places like MidwayUSA. The Midway LFAR buffers sure look a lot like KAK ones.
In hand, and measured, taken apart, I could not tell the difference between the 2.5" 5.3oz KAK and MidwayUSA one.
In hand, and measured, taken apart, I could not tell the difference between the 2.5" 5.3oz KAK and MidwayUSA one.
any kak part I've ever used has been fine. I will say the value line 308 barrels (green mtn blanks) perform very well for their price point and making a budget 308 build, not a bad go to
Proper gassing and buffer weight probably plays the biggest role in preserving brass.
agreed there, so far. i converted 3 rifles to left handed for suppressor use and used kak bcg’s in 2 of them. no problems yet as of 1000 rounds thru each.
in fact i felt like the bolt/bcg fit was maybe tighter than normal. maybe this will increase gas ring wear?
suppressed is hard on rings anyway, for me.
KAC went to a dual ejector bolt for similar reasons that we did it in large-frame guns:
-Makes the gun less sensitive to increased carrier velocity, i.e. unsuppressed to suppressed changeover and vice-versa with contemporary (not low backpressure) suppressors.
-Able to achieve higher ejection force without needing a crazy spring or messing with the extractor tension to ejector force ratio.
-Redundancy in ejection mechanisms; if one spring is damaged/worn or the ejector itself is seized or sluggish the other ejector will keep on working, though ejection force will be reduced.
We did a few other things in the evolution of the bolt, but from strictly a "why dual ejectors?" standpoint, those are the reasons.
-Makes the gun less sensitive to increased carrier velocity, i.e. unsuppressed to suppressed changeover and vice-versa with contemporary (not low backpressure) suppressors.
-Able to achieve higher ejection force without needing a crazy spring or messing with the extractor tension to ejector force ratio.
-Redundancy in ejection mechanisms; if one spring is damaged/worn or the ejector itself is seized or sluggish the other ejector will keep on working, though ejection force will be reduced.
We did a few other things in the evolution of the bolt, but from strictly a "why dual ejectors?" standpoint, those are the reasons.
