User Panel
User Panel
User Panel
|
Posted: 6/15/2018 11:19:13 AM EDT
Would this be a simple sign of overpressure or something else?
I have two lots of this stuff- one lot I have been using as my defensive ammo, all 556 rifles I own are zeroed to it, and I have had zero issues with it at all- perfect reliable function. I decided to accuracy test my new lot against it, to determine if I'd need to tweak my zero once I ran out of the current lot. First round pierced a primer, and a chunk of it went through the firing pin hole in the bolt face and wedged in between the firing pin and cam pin hole, locking the rifle up good. Got it cleared, tried two more, all resulted in pierced primers. Switched back to the "old" lot and had zero issues again. Rifle used is an SR15 MOD 2 with about 2500 rounds down the pipe- all 556 of varying flavors, never an issue. I've contacted the manufacturer and am waiting to hear back!  Attached File |
|
|
|
Posted: 6/15/2018 7:02:56 PM EDT
[#1]
Dont forget to add the lot number of the suspect ammo for others to cross check their own stuff.
|
|
|
|
Posted: 6/15/2018 9:07:40 PM EDT
[#2]
Does the brass date stamp say '13'?
Hard to tell from the picture. I remember some of the CBC 'Gold box' (not the new Magtech 'Green box') from 2013 had over pressure issues causing popped primers. All 4000rds of Magtech 77gr OTM I bought have Lot number of: 039/17 and 041/17 with brass case marked '17'. Shot about 1200rds of it without any problem through a couple of my KAC SR15 Mod1 and SR15 Mod1 LPR. I've find them to be more accurate than the 2014 lots I've tried. |
|
|
|
Posted: 6/16/2018 12:12:22 AM EDT
[#3]
I have a few boxes of the gold stuff laying around as well. Heavy ejector and extractor swipes in both a WOA wylde chambered spr barrel and a Spikes Tactical CHF 5.56 chambered barrel.
They shoot without these pressure signs in a DD 5.56 chambered CHF barrel. Interested in hearing what CBC has to say about the pressure signs. Post the lot number of you don't mind and I'll see if I can dig up boxes to compare. |
|
|
|
Posted: 6/16/2018 2:09:00 AM EDT
[#4]
Lots of blown primers with this in my mod 2 as well.
|
|
|
|
Posted: 6/16/2018 9:50:30 AM EDT
[#5]
and everyone likes to shit on IMI ammo. seems like alot of this going around lately. federal had it on their 77gr too.
|
|
|
|
Posted: 6/16/2018 12:30:35 PM EDT
[#6]
Lot is gold box, 013/14.
I've been shooting 024/15 with EXCELLENT results. But I'm not terribly happy to be sitting on 600 dollars worth of deadlined ammo right now that I simply don't trust. I'll post updates when I hear back. I did get a response that they are looking into it, but nothing beyond that yet. |
|
|
|
Posted: 6/16/2018 12:33:09 PM EDT
[#7]
Quote HistoryQuoted:
Does the brass date stamp say '13'? Hard to tell from the picture. I remember some of the CBC 'Gold box' (not the new Magtech 'Green box') from 2013 had over pressure issues causing popped primers. All 4000rds of Magtech 77gr OTM I bought have Lot number of: 039/17 and 041/17 with brass case marked '17'. Shot about 1200rds of it without any problem through a couple of my KAC SR15 Mod1 and SR15 Mod1 LPR. I've find them to be more accurate than the 2014 lots I've tried. Glad to see you've had no issues with the newer stuff. Did you notice that you had to alter your zero with newer lots or it just shot tighter? |
|
|
|
Posted: 6/16/2018 12:33:31 PM EDT
[#8]
Quote HistoryQuoted:
Lots of blown primers with this in my mod 2 as well. |
|
|
|
Posted: 6/16/2018 2:04:17 PM EDT
[#9]
Quote HistoryQuoted:
Lots of blown primers with this in my mod 2 as well. You've noticed the same with the IMI 77gr too, right? Makes me want to stick with BH. |
|
|
|
Posted: 6/16/2018 4:38:42 PM EDT
[#10]
Quote HistoryQuoted:
Lots of blown primers with this in my mod 2 as well. |
|
|
|
Posted: 6/16/2018 4:40:20 PM EDT
[#11]
Quote HistoryQuoted:
Lot is gold box, 013/14. I've been shooting 024/15 with EXCELLENT results. But I'm not terribly happy to be sitting on 600 dollars worth of deadlined ammo right now that I simply don't trust. I'll post updates when I hear back. I did get a response that they are looking into it, but nothing beyond that yet. |
|
|
|
Posted: 6/16/2018 5:22:42 PM EDT
[#12]
Quote HistoryQuoted: Yes they are headstamped 13, so that would make sense. Glad to see you've had no issues with the newer stuff. Did you notice that you had to alter your zero with newer lots or it just shot tighter? I went straight to 300 yards, and I remember it only required 1 click change to the elevation. I highly recommend buying more of the newer/current lot of Magtech 77gr OTM. |
|
|
|
Posted: 6/16/2018 5:29:25 PM EDT
[#13]
For anyone interested...I found this thread about the Older Gold Box CBC 77gr OTM not behaving well in SR15 Mod2
It seems like the older CBC Gold Box 77gr OTM w/ the black primer sealant won't function too well in SR15 Mod2's gas system. Seems like the length of barrel also matters too. All of my SR15 Mod1 16" rifles, including the Mod1 LPR, shot all of the old CBC Gold box and new/current Magtech Green box fine, no issues at all. I don't have a suppressor nor do I have anything shorter than 16", so I don't know how the CBC Gold Box will behave in SBR or with a Suppressor. I guess as of now, just buy the new Magtech Green Box 77gr OTM, and ignore the older CBC Gold Box 77gr OTM. |
|
|
|
Posted: 6/17/2018 8:01:56 AM EDT
[#14]
Quote HistoryQuoted:
For anyone interested...I found this thread about the Older Gold Box CBC 77gr OTM not behaving well in SR15 Mod2 It seems like the older CBC Gold Box 77gr OTM w/ the black primer sealant won't function too well in SR15 Mod2's gas system. Seems like the length of barrel also matters too. All of my SR15 Mod1 16" rifles, including the Mod1 LPR, shot all of the old CBC Gold box and new/current Magtech Green box fine, no issues at all. I don't have a suppressor nor do I have anything shorter than 16", so I don't know how the CBC Gold Box will behave in SBR or with a Suppressor. I guess as of now, just buy the new Magtech Green Box 77gr OTM, and ignore the older CBC Gold Box 77gr OTM. The stuff that functions fine in mine has green sealant, the stuff that doesn’t is black sealant. I’m going to see what magtech will do, hoping they will swap it out. We shall see. |
|
|
|
Posted: 6/17/2018 2:20:28 PM EDT
[#15]
One of mine is lot 013/14 as well, loaded with PR844 L-152/13 powder.
I also got the same results with lot 019/14 loaded with WC732 L-2475/14 powder. Significant pressure signs and no pierced primers, but a few popped primers. I went so far as to send the upper to WOA for them to evaluate the chamber since it runs ok in my DD barrel. They ran BH 262 ammo in it and sent the brass back along with a few other varieties that checked out ok as well. I'm of the opinion that the gold boxes are loaded hot. |
|
|
|
Posted: 6/17/2018 9:17:25 PM EDT
[#16]
For data collecting purposes...I've never have any problem with any CBC or Magtech 77gr OTM.
I guess it really depends on the barrel/chamber and ammo combination. My rifles used with CBC/Magtech were my SR15 Mod1 rifles, and SR15 Mod1 LPR. Per other guys' information posted above, it seems like the KAC SR15 Mod2 doesn't like the older CBC Gold Box, but functions fine with the newer Magtech Green Box. I've tried 017/14 (CBC Gold Box w/ Black Sealant)with no problem. I've tried 018/14 (CBC Gold Box w/ Black Sealant)with no problem. I've tried 024/15 (Magtech Green Box w/ Green Sealant) with no problem. I've tried 026/15 (Magtech Green Box w/ Green Sealant) with no problem. Also tried 039/17 (Magtech Green Box w/ Green Sealant) with no problem, and is the most accurate of all the batches I've tried. 
|
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
