User Panel
User Panel
User Panel
MS, USA
|
Posted: 5/11/2024 6:00:37 PM EDT
I had two cases separate today while zeroing a new load for my 300 RUM.
The brass is new from the box Nosler brass loaded with 104.5gns of US869 over a 208 ELDM. Load is very accurate and had zero pressure signs during the initial work up. The rifle is 7 years old and has never had this issue before in all the load work/shooting I’ve done with it. This load is to replace an old load with the same brass/bullet using retumbo. Any ideas? |
|
|
|
Posted: 5/11/2024 6:49:15 PM EDT
[#1]
What is the difference in base to shoulder datum of old brass and new?
|
|
|
|
USA
|
Posted: 5/11/2024 8:25:47 PM EDT
[#2]
Quote HistoryOriginally Posted By HighpowerRifleBrony: What is the difference in base to shoulder datum of old brass and new? Also, what's the difference in base to datum length between unfired (new), sized (unfired) and fired brass? |
|
|
MS, USA
|
Posted: 5/11/2024 11:09:05 PM EDT
[Last Edit: RUM]
[#3]
I measured the new brass fired vs un-fired, the difference was .010”. The older Nosler brass was .014” longer than the new unfired.
|
|
|
WI, USA
|
Posted: 5/12/2024 12:24:51 AM EDT
[#4]
Quote HistoryOriginally Posted By RUM: I measured the new brass fired vs un-fired, the difference was .010”. The older Nosler brass was .014” longer than the new unfired. That will do it; it's well below the minimum length specified by SAAMI. That brass should be returned for a refund - it never should have made it past QC. |
|
|
IA, USA
|
Posted: 5/12/2024 1:02:30 AM EDT
[#5]
Did you full length size the brass before you loaded it? NEVER FL size new brass you will get what happened to you.
|
|
|
MS, USA
|
Posted: 5/12/2024 7:01:06 AM EDT
[#6]
Quote HistoryOriginally Posted By tommee-boy-72: Did you full length size the brass before you loaded it? NEVER FL size new brass you will get what happened to you. Never have, it was loaded straight out of the box. I only neck size the 300 once I’ve fired the new brass. |
|
|
MS, USA
|
Posted: 5/12/2024 7:21:26 AM EDT
[#7]
Quote HistoryOriginally Posted By ronemus: That will do it; it's well below the minimum length specified by SAAMI. That brass should be returned for a refund - it never should have made it past QC. Quote HistoryOriginally Posted By ronemus: Originally Posted By RUM: I measured the new brass fired vs un-fired, the difference was .010”. The older Nosler brass was .014” longer than the new unfired. That will do it; it's well below the minimum length specified by SAAMI. That brass should be returned for a refund - it never should have made it past QC. Thanks for the input, I’ll given Nosler a call Monday. |
|
|
USA
|
Posted: 5/12/2024 9:53:21 AM EDT
[#8]
Quote HistoryOriginally Posted By HighpowerRifleBrony: What is the difference in base to shoulder datum of old brass and new? This First thing you need to check I always record measurements to confirm what my chamber dimensions are Then check new brass Factory brass you bought may be on the bottom end of tolerance and possibly thinner brass caused over stretch and failure |
|
|
USA
|
Posted: 5/12/2024 9:57:02 AM EDT
[#9]
Quote HistoryOriginally Posted By RUM: I measured the new brass fired vs un-fired, the difference was .010”. The older Nosler brass was .014” longer than the new unfired. That is a big difference and out of spec I had a RCBS FL size die that at full cam it pushed the should back .011” from my fired case dimension……my Forster FL die bumped .004 I sent the die to RCBS and they confirmed it was out of spec On average most FL sizing dies will bump at cam about .005ish. YMMV |
|
|
|
Posted: 5/12/2024 4:30:20 PM EDT
[#10]
OP, if they refund you, go get some Norma brass, it seems to be much better brass than the others except ADG as far as 300rum goes....
|
|
|
|
USA
|
Posted: 5/12/2024 5:59:17 PM EDT
[Last Edit: SteelonSteel]
[#11]
Yeah that’s a literal stretch. 8 thou is sketchy. 14 thou
 Although factory ammo can be that much shorter. SAAMI chamber spec and SAAMI ammo headspace checks are different numbers. You may be surprised at how short factory ammo can be. One way to salvage the short brass is to load a bullet in to the lands to let the shoulder blow forward instead of the base blowing back to the bolt face. You may want to ascertain your actual chamber headspace as well. More than once people have set their cam/lugs back. |
|
|
MS, USA
|
Posted: 5/12/2024 7:38:46 PM EDT
[Last Edit: RUM]
[#12]
Quote HistoryOriginally Posted By AKSnowRider: OP, if they refund you, go get some Norma brass, it seems to be much better brass than the others except ADG as far as 300rum goes.... Unfortunately I’m already invested heavily in Nosler, which makes this sting even more. I’m moving to ADG for my 7mm SAUM AR build. I shot Remington brass for 15yrs and never had any issue this severe. |
|
|
|
Posted: 5/12/2024 7:56:13 PM EDT
[#13]
Quote HistoryOriginally Posted By RUM: Unfortunately I’m already invested heavily in Nosler, which makes this sting even more. I’m moving to ADG for my 7mm SAUM AR build. I shot Remington brass for 15yrs and never had any issue this severe. I still run RP as well, still have around 1000 once fired cases.. We got my buddy some Norma in both 375H&H and 300Rum, brass is damn nice for the cost...But yeah Norma or ADG are tops right now for 300rum... |
|
|
|
PA, USA
|
Posted: 5/12/2024 9:51:22 PM EDT
[#14]
Annealing neck & shoulder may fix the defective brass. The case body, near the head must be stress relieved @ 485 F degrees .
|
|
|
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.
