View Full Version : Ejection patterns tell us ......
Ejection patterns tell us some information about how a gun is gassed. However, recently I put a BCM A5 buffer system in a SR15 and it runs great. Very happy with how it runs, it runs very smooth and a pleasure to shoot. But I noticed the ejection pattern with the carbine buffer was 2:00-2:30 and very hot per se, put in the A5 and love it. Oddly enough it shoots very smooth yet still ejects to 2:00-2:30.
I have never seen a gun run very smooth and have an awesome recoil impulse and lob the brass the direction the way this gun does so. Just interesting and thought I'd share and see if anyone else has experienced a similar set up.
PB
https://web.archive.org/web/20070202144326/www.armalite.com/library/techNotes/tnote34.htm
The ejection pattern of a rifle is created by a complex interplay of the opening velocity of the carrier group, and the extractor, ejector and their springs. In general, the faster the carrier group opens, or the stronger the extractor and ejector springs, the farther toward 12:00 (looking down on the rifle) the case is ejected. The weaker the springs are, or the slower the carrier group opens, the farther toward 6:00 the case is ejected.
Maybe it has something to do with the springs in the Knights bolt?
triggerjerk
10-31-23, 07:34
My 1st AR was an Anderson (cough, cough) 16 in carbine gassed. I knew nothing about these guns but did notice it ejected to the rear. Various factory ammo and various reloads of different components and powder charges. 6 or 800 or so rounds in, I sent a pic of dinged up cam pin to one who knows. He said he had cam pins with 4,000 rounds that didn't look as bad. Installed the advised adjustable gas block. When tuning from closed setting, if brass cleared the receiver, it went to 4:00. Later, I replaced extractor/spring and now observe the pie chart. Don't know if it really means anything or if it's simply a miniscule event in the annals of history....
BufordTJustice
11-02-23, 17:43
PB, I run a Vltor A5 system and LMT E-Carrier in my 16" SR15 Mod2.
Agreed on all points. KAC is doing different things, in a good way.
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PB, I run a Vltor A5 system and LMT E-Carrier in my 16" SR15 Mod2.
Agreed on all points. KAC is doing different things, in a good way.
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A5 and LMT E Carrier is good gear. I run A5’s in most of my AR’S. They have been great for me. And I have several E carriers. Add those two and an SSA, TRIFECTA, and life is generally good.
PB
BufordTJustice
11-02-23, 22:48
A5 and LMT E Carrier is good gear. I run A5’s in most of my AR’S. They have been great for me. And I have several E carriers. Add those two and an SSA, TRIFECTA, and life is generally good.
PB
Completely agree.
I know that the LMT E-Carrier on a new SR15 Mod2 is a different move.
I experimented with it after seeing a larger delta between PMC Bronze 55gr .223 and Frontier 62gr 5.56 NATO ammo than I wanted to see. PMC is weak AF, but otherwise good ammo. I found BCG velocity to be a little sluggish. Whereas with Frontier, it ran right but could be a little harsh.
I found the LMT E-Carrier added velocity in slow-end with the PMC and softened the stroke with the super-hot Frontier on the fast-end of BCG velocity.
I was running a BCM Mk2 T-0 (3.7pz IIRC) with Geissele Super 42 Rifle spring (their rifle spring works in the A5 system & with normal diameter buffers). Decided to try a BCM Mk2 T-1 buffer @ 4.6oz and an simply shocked at this amount of improvement in breadth of function, while still getting that comp-gun level of smoothness.
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I'm having as very similar situation but with a different set up. G$ 11.5 barrel (.070 carbine) running on a carbine RE with a standard spring and H3 and running suppressed with an OCL Polo K. In this set up it ejects at 2:00 ish but little gas to the face and isn't a bucking bronco. But I wanted to see if I could fine tune it so tried a Sprinco Red and Blue and neither will run without the can on it (which is a requirement for me.) So this past weekend I tried a G$ G42 spring with the H3 combo. Seemed to slow the bolt down a little based solely on recoil impulse but ejection pattern was still the same. I'm thinking go back to the Red and go down to H2 (which is one train of thought ie more spring less weight) or try the Hot White. Ultimately if I leave it alone I won't be upset but my OCD wants to find the "perfect set up." I know I know......
I should add running an RCA nitride BCG with Sprinco springs.
I'm having as very similar situation but with a different set up. G$ 11.5 barrel (.070 carbine) running on a carbine RE with a standard spring and H3 and running suppressed with an OCL Polo K. In this set up it ejects at 2:00 ish but little gas to the face and isn't a bucking bronco. But I wanted to see if I could fine tune it so tried a Sprinco Red and Blue and neither will run without the can on it (which is a requirement for me.) So this past weekend I tried a G$ G42 spring with the H3 combo. Seemed to slow the bolt down a little based solely on recoil impulse but ejection pattern was still the same. I'm thinking go back to the Red and go down to H2 (which is one train of thought ie more spring less weight) or try the Hot White. Ultimately if I leave it alone I won't be upset but my OCD wants to find the "perfect set up." I know I know......
I should add running an RCA nitride BCG with Sprinco springs.
I can only say that every time I tried to out weight the system, I felt more buck. So, yes I am in favor of less weight and more spring. Minimal experience playing with these but that has been my limited experience with H3's.
PB
I can only say that every time I tried to out weight the system, I felt more buck. So, yes I am in favor of less weight and more spring. Minimal experience playing with these but that has been my limited experience with H3's.
PB
I started with the H3 at the recommendation of the can maker. I mean, he wasn't wrong. It cycles everything with that set up and runs ok. At this point I am just playing around. I am pretty sure I have at least one H2 on the bench so I will get a Hot White and go to the range with springs and weights and see which one works best. I kind of like figuring these things out. Interestingly enough every other rifle I have is an A5 with a Green spring. And those shoot so nice I don't care where they eject lol.
Sparky5019
12-30-23, 19:06
Now that I’ve been messing around with this Frankenstein 416, I keep asking myself…
How does ejection pattern fit in when dealing with legit piston systems like the 416?
We think it has merit because it is an indirect indicator of BCG speed but is it really as big an deal as in a gas gun?
Shoot us a pic of your clone 416 and how is it running? Tell us about your build. I have buddy with a near perfect clone, but I have not shot that bad boy.
PB
Sparky5019
12-31-23, 08:24
Pics are taking forever to upload for some reason but here’s the build…
HK upper rec
Nefarious Arms chf 10.4 barrel
BRN BCG, vented gas block and pistol assy
Geissele 416 SMR
SOCOM RC2 (going to transition to RC3)
Geissele SD lower
HK spring and buffer
For the 416, it seems like the spring and buffer are fixed in the equation because the spring is the heaviest you’ll find on the market. I’ve tried all the others. lol.
The gun runs great overall but suppressed it ejects about 2:30 depending on rate of fire. Faster and it moves farther Forward as I would expect. I haven’t tried it on the FA lower yet. lol. It has about 1k rounds thru it so far. The gun itself is pretty heavy but it shoots super flat for recoil impulse. Way flatter than my gas guns of similar configuration.
I’ll try to get pics if I can ever get them to upload.
BufordTJustice
01-09-24, 10:42
Pics are taking forever to upload for some reason but here’s the build…
HK upper rec
Nefarious Arms chf 10.4 barrel
BRN BCG, vented gas block and pistol assy
Geissele 416 SMR
SOCOM RC2 (going to transition to RC3)
Geissele SD lower
HK spring and buffer
For the 416, it seems like the spring and buffer are fixed in the equation because the spring is the heaviest you’ll find on the market. I’ve tried all the others. lol.
The gun runs great overall but suppressed it ejects about 2:30 depending on rate of fire. Faster and it moves farther Forward as I would expect. I haven’t tried it on the FA lower yet. lol. It has about 1k rounds thru it so far. The gun itself is pretty heavy but it shoots super flat for recoil impulse. Way flatter than my gas guns of similar configuration.
I’ll try to get pics if I can ever get them to upload.
I don't know the weight for the HK buffer. I wonder if a PWS steel-body buffer could be incorporated (or if the HK buffer already has a heavier body mass than aluminum)?
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I don't know the weight for the HK buffer. I wonder if a PWS steel-body buffer could be incorporated (or if the HK buffer already has a heavier body mass than aluminum)?
https://hkguns.zenfolio.com/img/s/v-10/p3523344916-5.jpg
BufordTJustice
01-09-24, 11:59
https://hkguns.zenfolio.com/img/s/v-10/p3523344916-5.jpg
Gentleman AND a scholar. Thank you.
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Sparky5019
01-09-24, 12:00
Honestly I could use an H3 but I popped a RC3 on it to test and immediately got 3:15-3:30 ejection plus it runs well unsuppressed. Now if they’ll just release the FDE RC3s.
I have a mid gas Noveske skinny Afghan 14.5 barrel that while accurate is very over gassed. When first assembled it's ejection pattern was so far forward that other shooters came to me to mention it. I'm guessing 12:30-1:00. I'm using the BCM version of the Vltor A5 system. I was using their lightest buffer. I went to a Geissele Super 42 rifle spring and a BCM #3 buffer. That tamed it to 1:30-2:00. Next I added a LMT E carrier and the #4 buffer. Now it sits at around 3:00 so I'm happy. I have a BRT reduced gas tube so that's my next step but I think it's good for now.
We took a stock Colt 6920 last weekend and subbed an H2 for the H buffer that it came with. Shot 5 rounds each without changing my kneeling position, and the ejection was identical. H2 seemed to have a little more pop, but that could have been only in my mind. Decided to leave the H buffer installed.
Stock M4s come with H1 or H2 buffers, depending on barrel profile, and eject around 2:00 ish straight out of the box with military ammo.
Stock M4s come with H1 or H2 buffers, depending on barrel profile, and eject around 2:00 ish straight out of the box with military ammo.
Thats where my Colts spit. I'm so glad they leave .
Years ago, had a bunch of problematic HK416's.. fixed them with A5 tube & buffer.
This gas system can appear paradoxal (compared to a DI) in so far as if you under spring it or under buffer weight it it will slow the BCG rearward motion. The energy is captured in the (really) short stroke piston up front. In overcoming initial spring/buffer weight, in a very short space, it has enough inertia for the cycle.
Ejection patterns tell us . . . .
Where to pick up our brass.
Where to pick up our brass.
This bears repeating.
There was a funny spoof of the Ejection chart that illustrated the level of gayness in your ejection direction.
davidjinks
03-24-24, 11:07
I just shot SPR with my first ever suppressor. The ejection pattern went from a roughly 2ish to exactly 3 0’clock. Surefire SOCOM Mini 2, VLTOR A5 with A5H2 buffer, 18” Douglas MK12 barrel with rifle gas.
Ejection patterns tell us some information about how a gun is gassed. However, recently I put a BCM A5 buffer system in a SR15 and it runs great. Very happy with how it runs, it runs very smooth and a pleasure to shoot. But I noticed the ejection pattern with the carbine buffer was 2:00-2:30 and very hot per se, put in the A5 and love it. Oddly enough it shoots very smooth yet still ejects to 2:00-2:30.
I have never seen a gun run very smooth and have an awesome recoil impulse and lob the brass the direction the way this gun does so. Just interesting and thought I'd share and see if anyone else has experienced a similar set up.
PB
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