Peterson 375CT Brass early vs later lots 17 grain discrepancy, AMP 0151 vs 0165, neck thickness/tension

[secondofangle2]

my first 50 pcs of Peterson brass was directly from them in 2017, and my next 100 was from Grafs in May 2018. I hadn't paid attention and mixed them together. The other day I was loading some up and noticed markedly different seating force/neck tension between cases. I sorted them and today in the field there was a 50 fps difference between them.

I came home and weighed all my Peterson brass. There are clearly 2 lots: one, the lot of 50 cases from 2017, has a consistent case weight of 370 grains and a neck thickness of 0.012 and another, the lot of 100 cases from 2018, has a case weight about 386-389 grains and a neck thickness of 0.015. The AMP annealing codes generated from these lots are 0151 and 0165, significantly different as expected by the different neck thickness. Furthermore, I've been annealing with the earlier brass code, which probably means my later lots are under-annealed.

The H2O capacity is about 164.5 from the earlier lot and 163.5 from the later, heavier lot; my bertram is 166 and all this comports with my previous observations over the years of Bertram having higher capacity (and case weights of about 360 grains.

Anybody know what the current Peterson offering weighs and has as case capacity? My 50 fps difference in the field today seems a bit extreme, but when neck tension and case capacity are significantly different....especially when you're near 100% capacity with RL50 and a 390 ATIP

 

[MarcC11B]

I haven’t bought any more Cheytac Peterson brass in a while but will measure them compared to my current stock when I do. I did get 100 more pieces of Peterson 33XC brass in and its rim is larger by enough that it won’t fit in my #14 RCBS shell holder, like the last batch and my .338 Lapua brass (Lapua). It will barely fit the #35 Redding.

 

[badassgunworks]

Headspacing if off on cheytac as well

 

[secondofangle2]

Please tell more

 

[badassgunworks]

Please tell more

Off from the orig. Ring to datum measurements submitted by ptg on the previous saami spects but i guess that is needed sence there is so many variations Out. One size does not fit all sence there is variations a,b,c,d,e,f then there is perhaps the cheytac current owners revisions. Who knows what that is if its changed at all. Last revision was most common used by cheytac usa revision f dated back on 2015 this makes it difficult for a manufactor to get brass to fit in all chambers last batch i checked was compaired to f revision reamer print and brass was off .017 short before fireformed.

 

[232593]

my first 50 pcs of Peterson brass was directly from them in 2017, and my next 100 was from Grafs in May 2018. I hadn't paid attention and mixed them together. The other day I was loading some up and noticed markedly different seating force/neck tension between cases. I sorted them and today in the field there was a 50 fps difference between them.

I came home and weighed all my Peterson brass. There are clearly 2 lots: one, the lot of 50 cases from 2017, has a consistent case weight of 370 grains and a neck thickness of 0.012 and another, the lot of 100 cases from 2018, has a case weight about 386-389 grains and a neck thickness of 0.015. The AMP annealing codes generated from these lots are 0151 and 0165, significantly different as expected by the different neck thickness. Furthermore, I've been annealing with the earlier brass code, which probably means my later lots are under-annealed.

The H2O capacity is about 164.5 from the earlier lot and 163.5 from the later, heavier lot; my bertram is 166 and all this comports with my previous observations over the years of Bertram having higher capacity (and case weights of about 360 grains.

Anybody know what the current Peterson offering weighs and has as case capacity? My 50 fps difference in the field today seems a bit extreme, but when neck tension and case capacity are significantly different....especially when you're near 100% capacity with RL50 and a 390 ATIP

My lot from 2017 which has similar weights to yours generated a 0156 AMP code. And it seems to have stretched the case length by .008. Did you observe any stretching of the case after annealing?

 

[232593]

my first 50 pcs of Peterson brass was directly from them in 2017, and my next 100 was from Grafs in May 2018. I hadn't paid attention and mixed them together. The other day I was loading some up and noticed markedly different seating force/neck tension between cases. I sorted them and today in the field there was a 50 fps difference between them.

I came home and weighed all my Peterson brass. There are clearly 2 lots: one, the lot of 50 cases from 2017, has a consistent case weight of 370 grains and a neck thickness of 0.012 and another, the lot of 100 cases from 2018, has a case weight about 386-389 grains and a neck thickness of 0.015. The AMP annealing codes generated from these lots are 0151 and 0165, significantly different as expected by the different neck thickness. Furthermore, I've been annealing with the earlier brass code, which probably means my later lots are under-annealed.

The H2O capacity is about 164.5 from the earlier lot and 163.5 from the later, heavier lot; my bertram is 166 and all this comports with my previous observations over the years of Bertram having higher capacity (and case weights of about 360 grains.

Anybody know what the current Peterson offering weighs and has as case capacity? My 50 fps difference in the field today seems a bit extreme, but when neck tension and case capacity are significantly different....especially when you're near 100% capacity with RL50 and a 390 ATIP

What was the lot # from the 2017 brass?

 

[secondofangle2]

No idea at this point. One of the first though.

 

[secondofangle2]

My lot from 2017 which has similar weights to yours generated a 0156 AMP code. And it seems to have stretched the case length by .008. Did you observe any stretching of the case after annealing?

Weigh your cases with code 156. I give long odds that they weigh 370 +\- not the 388 +\- of the later lots. And measure neck thickness too. I actually prefer the earlier offering bc it’s closer to Bertram. Honestly I like Bertram better than Peterson but that’s probably just bc of 10 yrs of familiarity

 

[232593]

Weigh your cases with code 156. I give long odds that they weigh 370 +\- not the 388 +\- of the later lots. And measure neck thickness too. I actually prefer the earlier offering bc it’s closer to Bertram. Honestly I like Bertram better than Peterson but that’s probably just bc of 10 yrs of familiarity

I did, 48 of them were 371-372.9 grains. Two outliers one at 370 and another at 374.

I do have about 200 unfired and once fired Bertram cases I guess I’ll have to use now. No lot numbers to go off of though. Guess I’ll have to use those from now on since I’m down to only 76 Peterson cases due to the annealer incident

 

[secondofangle2]

I did, 48 of them were 371-372.9 grains. Two outliers one at 370 and another at 374.

I do have about 200 unfired and once fired Bertram cases I guess I’ll have to use now. No lot numbers to go off of though. Guess I’ll have to use those from now on since I’m down to only 76 Peterson cases due to the annealer incident

sounds about right to me

 

[232593]

sounds about right to me

Did you get a 0151 code from the cases in the 386 grain range?

 

[secondofangle2]

No it was higher. I’ll report back later. I think it was 0170ish

 

[secondofangle2]

Anybody recently measure the H2O capacity of current issue Peterson 375 Cheytac brass?

 

[Sigma]

Anybody recently measure the H2O capacity of current issue Peterson 375 Cheytac brass?

 

[secondofangle2]

Excellent thanks. That’s Waaaaay less capacity than Bertram which is closer to 167 grains.

I’ll be sticking with Bertram till I ru nout

 

[amymorgan20]

Anybody recently measure the H2O capacity of current issue Peterson 375 Cheytac brass?

I haven't, but I have checked headspace and the latest production brass (2021 & 2022) I have shows the new brass is 0.014" shorter than fired brass.

 

[Sigma]

I haven't, but I have checked headspace and the latest production brass (2021 & 2022) I have shows the new brass is 0.014" shorter than fired brass.

it seems most cheytac brass is, compared to my fired 338 cheytac, both my virgin peterson and bertram is anywhere from 8-12 thou short on headspace

 

[amymorgan20]

it seems most cheytac brass is, compared to my 338 cheytac, both my virgin peterson and bertram is anywhere from 8-12 thou short on headspace

Oh wow, Bertram too? yikes

 

[Dogtown]

it seems most cheytac brass is, compared to my fired 338 cheytac, both my virgin peterson and bertram is anywhere from 8-12 thou short on headspace

When I first started shooting .408CT in 2006, the first batch of Bertram brass I got I loaded LRBT 419s and RL25 to work up a pressure ladder. Most of the brass came out of the chamber with weird dents I’d never seen before and when I compared the the headspace on the few non-dented pieces, the virgin brass had crazy excessive headspace. Something like 0.30”. I could visually see the difference with the brass lined up. Cheytac sent me a new batch after much consternation (the Walrus was convinced I somehow re-sized the virgin brass before loading), and problem solved, but that Bertram brass back then was so damned soft it didn’t last more than three or four firings. I even got some EDM head stamped brass that was also on the soft side and later Bill Ritchie confirmed it was made to spec by Bertram. It wasn’t until Jamison started making .408 brass that I think we finally got a good source, and then those guys imploded.

That’s my amazing contribution to this thread.

 

[Sigma]

When I first started shooting .408CT in 2006, the first batch of Bertram brass I got I loaded LRBT 419s and RL25 to work up a pressure ladder. Most of the brass came out of the chamber with weird dents I’d never seen before and when I compared the the headspace on the few non-dented pieces, the virgin brass had crazy excessive headspace. Something like 0.30”. I could visually see the difference with the brass lined up. Cheytac sent me a new batch after much consternation (the Walrus was convinced I somehow re-sized the virgin brass before loading), and problem solved, but that Bertram brass back then was so damned soft it didn’t last more than three or four firings. I even got some EDM head stamped brass that was also on the soft side and later Bill Ritchie confirmed it was made to spec by Bertram. It wasn’t until Jamison started making .408 brass that I think we finally got a good source, and then those guys imploded.

That’s my amazing contribution to this thread.

the OG 408 CT jamison is what my current 338-408 was started on (in its previously owned life by my gunsmith). I still have around 50 pieces left of it (at end of life its life though), it served him pretty well but he was putting clear nail polish over the primers to hold the primers in after not long.

 

[badassgunworks]

Its a simple fix. Headspace off brass and or create a false shoulder and jamb into lands to fireform

 

[amymorgan20]

Its a simple fix. Headspace off brass and or create a false shoulder and jamb into lands to fireform

I am going to try this with a few virgin pieces of brass, but to fireform my entire stock of brass just to get it properly to the right headspace for my chamber is an investment in projectiles and powder I cannot afford. With prices and unavailability of components, I'm just going to have a new barrel spun up with headspacing of the virgin brass.

 

[232593]

When I first started shooting .408CT in 2006, the first batch of Bertram brass I got I loaded LRBT 419s and RL25 to work up a pressure ladder. Most of the brass came out of the chamber with weird dents I’d never seen before and when I compared the the headspace on the few non-dented pieces, the virgin brass had crazy excessive headspace. Something like 0.30”. I could visually see the difference with the brass lined up. Cheytac sent me a new batch after much consternation (the Walrus was convinced I somehow re-sized the virgin brass before loading), and problem solved, but that Bertram brass back then was so damned soft it didn’t last more than three or four firings. I even got some EDM head stamped brass that was also on the soft side and later Bill Ritchie confirmed it was made to spec by Bertram. It wasn’t until Jamison started making .408 brass that I think we finally got a good source, and then those guys imploded.

That’s my amazing contribution to this thread.

Can’t believe I missed this earlier.

In your time shooting the .408 did you ever try RL50 or H50BMG with the 419 or 420 grain bullets? If so do you have a recommended starting charge weight?

 

[Dogtown]

I can't remember which specific one I used (probably H50BMG), but it was way too slow. Like 250fps slower compared to RL25.

 

[232593]

Thank you!!!

I have RL25 as well. Would I be safe starting at 125 grains and working up? I’m told 130 or 135 is max for RL25

 

[Dogtown]

Yeah, that sounds reasonable though caveat emptor. I don't have that rifle/data anymore so I'm not 100% sure. Someone on the Hide should be able to give you good up to date load data.

 

[232593]

I have a thread on the reloading forum but no responses yet.

 

[Dogtown]

@232593 here are some suggestions with Quickload using Cutting Edge 420gr MTAC as an example

From that list it looks like RL33 would be ideal, with N570 & H1000 not far behind. Unfortunately those are hard to get powders, but drilling down a bit on those to see a ballpark of charge weights to think about....

RL33

N570

H1000

Again, this is NOT a replacement for actual load data, but this should at least give you an idea of where to start.

 

[232593]

@232593 here are some suggestions with Quickload using Cutting Edge 420gr MTAC as an example
View attachment 8158398

From that list it looks like RL33 would be ideal, with N570 & H1000 not far behind. Unfortunately those are hard to get powders, but drilling down a bit on those to see a ballpark of charge weights to think about....

View attachment 8158402
RL33

View attachment 8158404
N570

View attachment 8158405
H1000

Again, this is NOT a replacement for actual load data, but this should at least give you an idea of where to start.

Awesome thank you. I know I have 10 LBs of RL25, have to see how much N570 I have

 

[MarcC11B]

In the.408 I had RL50 & 50BMG were too slow. RL25 was good but RL33 gave superior velocity with the 415 MTH. RL25 topped out about 2850 fps and RL33 got over 3000. I ran it very comfortably at 2900 as it gave the best groups.

 

[232593]

In the.408 I had RL50 & 50BMG were too slow. RL25 was good but RL33 gave superior velocity with the 415 MTH. RL25 topped out about 2850 fps and RL33 got over 3000. I ran it very comfortably at 2900 as it gave the best groups.

Did you get pressure at 2850 with RL25? Reason I ask is both of my guns seem to like 2850 with the 420 bullets I’m using.

I have not seen any RL33 in ages, I have a lot of RL25 and about 6 LBs of N570 on hand and am looking into sourcing some H1000 per the data dogtown posted.

Thank you

 

[MarcC11B]

I got pressure at about 2900 fps, which was somewhere around 2 more grains of powder if memory serves me right.

 

[232593]

I got pressure at about 2900 fps, which was somewhere around 2 more grains of powder if memory serves me right.

I didn’t get pressure until 134 grains of RL25. But I was using a different bullet (420 RMB).

I started a .408 thread here:

408 Cheytac loads

I did not see a .408 reloading thread so figured I’d make one. I did a pressure test with RL25 with 420 grain Parker Productions (Formerly known as RMB) this weekend. I loaded them .025 off the lands At 134 grains I saw pressure signs start to show on the brass. No heavy bolt lift. From...

www.snipershide.com

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