308 semi auto suppressed issues

rifleman1981

rifleman1981

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Minuteman
Jan 8, 2010
590
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nw oklahoma
#1
For starters I own a small commercial ammunition manufacturing company, and I also guide hog hunts suppressed with thermal and I'm starting to get a little discouraged. I've ran several high quality semi auto 308 platforms, and have had hell with all of them suppressed, I don't run junk, I had a pof 308 starting out, and had hell with it getting dirty and not functioning like is should, so I sold it and bought a ptr. The ptr will always extract but it doesn't always get the case out of the way and smashes it and jams the rifle occasionally, so I shit canned it and bought an lwrc repr. The repr, is no better suppressed than the other two, after about 15 or 20 rounds it doesn't eject like it should and it blows so damn much gas back in your face that without glasses your eyes burn and it gets hard to shoot. I'm not a novice in the suppressor field, or the ar10 field but this shit is getting irritating. I went to a xsr side charging upper on my ar15 rifles and that stopped the gas in the face issues, and I've never had a 556 malfunction like the 308's do when suppressed, and I'm assuming that's because there's not near the blowback with a 556 like there is with a 308. Any suggestions on how to stop all the bullshit issues with a suppressed 308?
 
#4
Your reliability problems are almost certainly the result of being over-gassed. Had the same problems with my DPMS 243 when I first went suppressed.
The adjustable gas block will allow you to fine-tune the amount of gas going back into the BCG.
As for it getting dirty quick... sorry, that's just part of shooting a direct-impingement AR10 suppressed. I don't think there are many companies offering piston-driven AR10s (yet), but that would help. I know my Piston 223 runs much cleaner suppressed than my DI 243.
 
#6
I'm familiar with the adjustable gas block settings on both the lwrc and the pof, after the gun gets dirty on the suppressor setting on the lwrc or the pof, function goes to shit in a hurry. I don't mind having to clean a rifle but I hate to have my shit not function and not be able to run a full mag after someone pays me to kill a pig
 
#7
Of corse not, why would I pay $3000 for a repr that is piston driven and then try to adjust it to the suppressor setting? Yes I've adjusted them, I've tried loading cleaner powders, I've backed loads off, and I'm still having problems. I was actually looking for soulitions not smart ass remarks.....
 
#8
What year repr do you have? Sounds like the newer mkII if you are getting gas in your face as the first gen is a side charger and has zero blowback as well as 4 position gas block. Never had an issue suppressing the gen I with various suppressors on the 20" or the 12.7". The company went through a change of ownership since my purchase and the new mkII line and is not what it once was. If at least the lwrc customer service is still the same, they should be able to help you out.
 
#9
It is a side charger, that little channel on the side that the charging handle slides in is like a jet nozzle and sprays my face with gas bad..... it has the 4 position bloc as well. I'd say the rifle is 3 or 4 years old.
 
#10
Still sounds like a gas block thing. If you have the 4, turn it to off and see if is actually working (stopping all the gas). Based on your tag line, I think you need to visit whoever sold you that lemon. :D
 
#11
The gas block, adjusts the piston system so the op rod isn't over zealously cycling the bolt, what gets in your face is blowback from the suppressor coming back down the barrel. There have been many more people than just me having the same issues......
 
#12
#13
... and when you set it to off, nothing cycles - rod doesn't move - bolt doesn't open at all. The gas block is completely closed. It becomes a bolt action rifle. If the bolt doesn't open then gas cannot exit in any way from the rear. Reload with the side charger, wash, rinse, repeat.
The point of setting it to off is to see if the gas block you have is indeed regulating the amount of gas to any extent. If it is set to off and the bolt opens even the slightest, you have a bad gas block.
(shrug) first I've heard of your/this problem with the gen 1 repr. I've had mine since 2009 and actively read their forum until the change in ownership a few years ago.
I don't experience any gas funneling through the side charger back towards the face. On the gen 1 repr, the back of the upper does not have any opening; the gas coming back down the barrel escapes through the ejection port or I guess (in your case) through the small openings of the side charging handle, but that is like an ejection port -- the gas is exiting 90 degrees to the barrel. It is not like an ar15 where it comes back through the rear charging handle openings and directly into your face.
 
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#15
Sounds like a place for a Scar 17.

No problems suppressed with that. I have a POF308 that is 100% also except for a stuck case now and then. I need to polish the chamber on it.
 
#16
I know it is popular to hate on KAC, but I have four SR-25 rifles and run the KAC full size 7.62 can on all of them. They all run 100% with Federal Gold Medal Match, Federal Tactical Bonded, Speer Gold Dot, as well as all of my own loads using 175-class bullets and Varget, 4064, 4166, and Reloder 15.

If you're looking for a new platform you might consider KAC. Their can has the lowest backpressure of any 7.62 can I've shot. I have a LaRue can on the way, but I've not been behind one yet, so I can't comment on it, but I've heard good things.
 
#18
for the third time, it's to test if the gas block is even adjusting any gas. Or switch from the normal setting to the suppressed setting and see if the brass ejecting at the same angle. If yes, your gas block is not adjusting at all.
 
#22
As I stated, I was familiar with the adjustable gas block, shitty comments, like for the third time, usually get shitty replies. I'm an 07/02 sot, and this is far from the first issue that I, or a couple of customers have had with an ar10 platform. Past the gas block issue, I'm asking what else could be causing issues.
 
#24
Have you played with buffer weights? Buffer springs? It's hard to diagnose a gun over the internet, but it shouldn't be running that poorly. My only experience with a suppressed ar10 is a dpms pos, but besides the blowback, it at least has usable reliability.
 
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#25
yet you still don't know what the problem is nor how to fix it. that says volumes.
I've cranked out a couple form 1 suppressors myself so I'm not impressed.
enjoy your misery.
thanks for reminding me why I stay away from forums and mingling with the trash of society.
2stupid2function.gif
 
#26
I wasn't trying to impress anyone, just saying I wasn't a novice. I've built a few auppressors myself, I do know it's not a gas block issue, I have not played with any buffer weights at all, that might be something worth trying.
 
#27
Did you view the utube link stwcattle posted? Gas regulation and mass regulation are two ways of solving the same problem of bolt velocity. If reducing the bolt velocity by adjusting, reducing the gas flow didn't solve the issue, adjusting the buffer weights won't work either.
 
#29
Potentially, but not guaranteed. Your issue is still strange. Have you tried reaching out to the manufacturer? Most of them are fairly helpful.
 
#32
Your problem(s) will not be solved by adjusting the gas metering or the reciprocating mass. There is a quantity of gas produced when firing and, unsuppressed, a lot of it finds it's way out the muzzle. With a suppressor though, you've corked the one end so everything flows back in the other direction. You can try a cleaner-burning powder or fit a larger-volume can to (maybe) extend the time between stoppages.
 
#34
kl3309 said:
Your problem(s) will not be solved by adjusting the gas metering or the reciprocating mass. There is a quantity of gas produced when firing and, unsuppressed, a lot of it finds it's way out the muzzle. With a suppressor though, you've corked the one end so everything flows back in the other direction. You can try a cleaner-burning powder or fit a larger-volume can to (maybe) extend the time between stoppages.
Click to expand...


Wrong. Barrel length, gas system length, port pressure, buffer weight and bolt weight all play a part in how a rifle runs suppressed. It takes time to tune everything and get a rifle to run properly. I had a hell of a time with my first 308, but finally got it running reliably with a suppressor....and no gas in the face.

You want to manage the gas and bolt velocity. With a suppressor you have an increased amount of back pressure which sometimes can't be managed by an adjustable gas block alone. Adding mass to the buffer or increased spring weight can and will keep the bolt locked a little longer allowing the pressure to drop, and reduce the gas/fouling coming back into the action. Increased mass in the reciprocating components also provides a "dead blow" affect to help overcome fouling and drive the bolt into battery.

Here is a good video explaining it. Since you have a piston gun you obviously can't use that bolt, but it helps with explaining how increasing mass can help.

https://youtu.be/tRisytKeZoc

My first 308 acted just like yours when I got it. It would jam and quit functioning after 20 to 25 rounds and would kick the brass out at 1'o clock with the gas block adjusted per instructions. My brass was also getting the shit beat out of it. I replaced all the steel weights in my rifle length buffer with tungsten ones and increased the mass significantly. By adding weight, my brass was now ejecting around 3'o clock, was in much better condition and my rifle runs significantly cleaner. I have put 300 rounds or so through it since I added the weight and even shot 100 rounds in one afternoon without a single malfunction.
 
#36
rifleman1981 said:
That's what I've decided, I've got video of the problems I'm having is anyone wants to see.....
Click to expand...

Send me the video please, by chance are you a member of the LWRC forum. An adjustable gas block does not make everything right at all times. No two suppressors have the same internal spec's back pressure, Etc. In what shape is your brass being ejected(beat up/dentedmouths)? Is your brass being ejected between 230 - 400 clock? The prblem sound like the gas port needs to be opened up, just my 2 cents. With the Repr it needs to be tuned to the can, LWRC will send you a RMA to send the Repr and you will need to send the can in also to them. Video and picture of brass would help, I would not change any thing on the repr yet. Let LWRC look at it, Repr's run great I own one. How long is you barrel?Simple fix, look at this post over at LWRC: http://forum.lwrci.com/viewtopic.php?f=30&t=15786

Ejection chart: https://www.google.com/search?ie=UTF...bs2IQv5XdG0sM:

Are you over gassed or short stroking?
 
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#37
I am using an Ops Inc 3rd Model on my Armalite AR10b with a 20" WOP 1:10" barrel and Superlative AGB in use as a conventional AGB, not vented (tears up my can covers). One of the principle reasons I chose this can, besides the fact I was already using a 12th Model on my MK12, was that Mr. Seberger's design had been proven by some pretty finicky folks who depend on reliability with their lives. They ran this can on their HK21 LMGs. Even Ops Inc's website (http://www.opsinc.us/suppressors/3rd...-M240-MBS.html) tells the tale of 1400 rds in 15 minutes. It's not for everyone, though as it's 31ozs. I have yet to have cycling issues with my big-bore ARs. I was impressed enough to have GA Precision make my .260 GAP10 to accept the same can. No issues with it either.

AR10 [IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i682.photobucket.com\/albums\/vv190\/nukemmc\/AR10\/20160816_182402_zpsn27o0sx6.jpg"}[/IMG2]



GAP10 G2 - same can: [IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i682.photobucket.com\/albums\/vv190\/nukemmc\/GAP10%20G2\/20170424_224133_zpsq2wayw7w.jpg"}[/IMG2]



Now the bad news. Ops Inc is defunct. On a good note, Ron Allen (http://aesuppressors.com/suppressors/AE30.html) was the principle manufacturer of the Ops Inc cans and now produces very similar products under his own name. His cans at least use 5/8-24 threads instead of the oddball 11/16-24 that OPS Inc used. Might be worth a try. Not sure what makes it function so well in semi/full auto weapons, but one distinctive feature is the rather robust initial chamber that is over the barrel. [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/patentimages.storage.googleapis.com\/pages\/US4907488-1.png"}[/IMG2]
 
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#38
Your problem with your Repr is an easy fix by LWRC for Repr's with 2 or 4 pos AGB. If it is short stroking (under gassed) in silenced mode you could switch it over to normal and see if it's better. I'm not sure if you have a 2 or 4 pos AGB. It won't hurt anything to try it in normal mode, try and have some one look and see which area the brass is ejecting.
This is dealing with the 20 Pos AGB from LWRCC: If you are using a standard factory ammo; turn the adjustment valve to closed (clockwise until it seats), then back it out 16 clicks and fire 3 rounds. If the ejection is at 2:30 or less; close it (counter-clockwise) two clicks and test again. Ideal is to have an ejection between 2:30 and 4:00 (standard for AR platforms). You should see little, if any impact shift in this process.

Using a suppressor is a different animal. Different suppressors create different back pressures. Also, some suppressors will have an impact shift that can be quite substantial compared to others. That said, when shooting suppressed, start by closing the adjustment valve, then open to six clicks. Test fire and check ejection. With some suppressors, it may be difficult to get a perfect ejection, but the rifle will tell you where it is happiest.
 
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#39
NukeMMC said:
I am using an Ops Inc 3rd Model on my Armalite AR10b with a 20" WOP 1:10" barrel and Superlative AGB in use as a conventional AGB, not vented (tears up my can covers). One of the principle reasons I chose this can, besides the fact I was already using a 12th Model on my MK12, was that Mr. Seberger's design had been proven by some pretty finicky folks who depend on reliability with their lives. They ran this can on their HK21 LMGs. Even Ops Inc's website (http://www.opsinc.us/suppressors/3rd...-M240-MBS.html) tells the tale of 1400 rds in 15 minutes. It's not for everyone, though as it's 31ozs. I have yet to have cycling issues with my big-bore ARs. I was impressed enough to have GA Precision make my .260 GAP10 to accept the same can. No issues with it either.

AR10 [IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i682.photobucket.com\/albums\/vv190\/nukemmc\/AR10\/20160816_182402_zpsn27o0sx6.jpg"}[/IMG2]



GAP10 G2 - same can: [IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i682.photobucket.com\/albums\/vv190\/nukemmc\/GAP10%20G2\/20170424_224133_zpsq2wayw7w.jpg"}[/IMG2]



Now the bad news. Ops Inc is defunct. On a good note, Ron Allen (http://aesuppressors.com/suppressors/AE30.html) was the principle manufacturer of the Ops Inc cans and now produces very similar products under his own name. His cans at least use 5/8-24 threads instead of the oddball 11/16-24 that OPS Inc used. Might be worth a try. Not sure what makes it function so well in semi/full auto weapons, but one distinctive feature is the rather robust initial chamber that is over the barrel. [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/patentimages.storage.googleapis.com\/pages\/US4907488-1.png"}[/IMG2]
Click to expand...

The OpsInc design is magic, I see you are running your AGB closed if I have it right. I wonder If AE design works the same as the OpsInc?
 
#40
agbm said:
The OpsInc design is magic, I see you are running your AGB closed if I have it right. I wonder If AE design works the same as the OpsInc?
Click to expand...

Yes, I am running the Superlative about 1 1/4 turns open (5 clicks) as a conventional gas block on the AR10. When I ran it vented, I had it wide open and still functioned 100%. The SLR gas block on the GAP10 is about 3 clicks open.

Since Ron Allen used to make the cans for Mr. Seberger, I would bet the cans function in the same manner. I am pretty sure the AE30 is a 2" shorter version of the OPS Inc 3rd Model with only 2.5" over the barrel instead of 5". 7.25" past the muzzle when mounted for the 3rd Model and 8" for the AE30. After OP died in 2010, I am not sure how the patent /licensing went and how Ron picked it up. Regardless, I have heard nothing but good from folks with AE cans. I bought mine post 2010, so I talked with Ron about a couple technical questions even though they were OPS Inc cans.
 
#42
djarecke said:
Do you have to have a barrel profiled for the AE cans and use their brake or is there a direct thread model?
Click to expand...

The 3rd Model and the AE30 do not use a brake/collar arrangement. The barrels on my bolt rifles get a 20deg taper about 4.5" back from the muzzle (2.5" for an AE30) and the muzzle is threaded 11/16-24 (5/8-24 for an AE30). My 12th Model uses a brake/collar arrangement. My AR10 and GAP10 have 11/16-24 threaded muzzles but since the barrels are .875" and not thick enough (must be >0.920" to properly seat the taper) I have collars on the barrels that add the extra diameter

You can see it on the GAP10:
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i682.photobucket.com\/albums\/vv190\/nukemmc\/GAP10%20G2\/20170424_223905_zpstiwtpfd5.jpg"}[/IMG2]

AR10 collar:
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i682.photobucket.com\/albums\/vv190\/nukemmc\/AR10\/20170208_140013_zps7raf8pq5.jpg"}[/IMG2]
 
Last edited:
#44
HK has a nice piston driven AR10 type rifle and it is designed to work reliably with the OSS suppressor. It might be worth taking a look at.
Sig also has a piston driven one at a much cheaper price.
 
#45
I've run a suppressed 16" REPR for 5 years and never had any problems. I'm not sure how many rounds the rifle has on it, but it is over 3,000. Most of them factory Black Hills and FGMM, but it has a bunch of 175 SMKs over 44 grains of Varget as well. What kind of ammo are you feeding these rifles?
 
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