390 grain Hornady A-Tip load development 375 Cheytac
- Thread starter secondofangle2
- Start date
No ...Just grade 350 MSP..... at 2500yds it doesn't need to be AR series..
1/4” or 1/2” thickness?1 mile......... same grd 350 Plate...bit worse for wear here!!!
Atips...
I would say that it is. Primer pockets hold up well, consistent weight. From my testing Bertram seems to do a bit better at higher charge weights of RL50 and the ATIPs.
Hot as shit today at the range, 109 according to the range thermometer.
I put a .401 neck bushing on my load and dropped the charge down to 135.5 grains of H50BMG. It dropped my ES a bit, but still not in my desired single digit range
I did some testing with RL50, Peterson Brass and ATIPS. I opened a brand new container of RL50 and this is what I got. No additional neck tension.
The good part of RL50 is it would seem so far that it’s fairly resistant to powder humidity effects on velocity. Last week’s pressure test yielded 2901 at 135 grains. Today I got an average of 2889. Only a three round sample but I’m slightly optimistic (although I shouldn’t be because I have shitty luck)
I put a .401 neck bushing on my load and dropped the charge down to 135.5 grains of H50BMG. It dropped my ES a bit, but still not in my desired single digit range
I did some testing with RL50, Peterson Brass and ATIPS. I opened a brand new container of RL50 and this is what I got. No additional neck tension.
The good part of RL50 is it would seem so far that it’s fairly resistant to powder humidity effects on velocity. Last week’s pressure test yielded 2901 at 135 grains. Today I got an average of 2889. Only a three round sample but I’m slightly optimistic (although I shouldn’t be because I have shitty luck)
Those tests were done at a range that only went out to 500 meters.
There is another one a ways away that goes to at least 1k
2000yds.... a 390gr that didn't quite make it to the right spot!! 
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Past 2000 conditions have to almost perfect to see an impact location from a Lazer. I almost never miss seeing ours with an Atip.
@wooferocau I think I’m going to try your load this weekend. I’m getting single digit ES but they are grouping at 3/4”. I know you’re at .020 off the lands. Is it 134 or 134 grains of H50BMG that your using?
Dammit, I literally just stocked up on 200 lazers, which ain't cheap. Now I am going to have to give the atips a try.
Not to derail this thread but I acquired some 425 grain .408 Lasers too. Starting to wish I didn’t and I’m starting to wish Hornady would make some .408 ATIPS. How far off the lands do you load your Lasers?
133
Just a note.... i was always using FED 215m primers...but some time ago i switched to REM 9 1/2 Magnum which low and behold i find perform slightly better than the 215,s..
I use the 215s as well. Did you change anything on your load when you switched to the Rems?
215,s here in Aus are unobtainable.... I do have a large supply on hand luckily, but when i was trying to source more i came across the REM,s and they were extremely cheap !! Thought id give them a try and to my surprise i found they seem to perform better than the 215,s..
Warner told me the 361’s wouldn’t stabilize in a 1:10.5 so if your buddy has success with the factory barrel please let me know.
What powder is he using?
Personally i am not to worried about getting the most velocity from the 390,s...barrel life has turned out way way better than i originally envisaged, and accuracy at the distances i shoot is just fantastic!!!
The 375 in the DT has produced the best results at long range that i have achieved...so very happy with the current config!!
The 375 in the DT has produced the best results at long range that i have achieved...so very happy with the current config!!
Yeah...BUT!!! He also uses the Berger 379,s ( as have i ) and they "theoretically" shouldn't work also...BUT they perform brilliantly.........Only downside is that we purchased ALL the available stock in Aus...with no more to come...AND...they are circa $6-50 each!!
135gr AR 2218 with the band just forward of the case mouth...
50bmg and 375 with the Berger 379
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Not sure yet, this is my first load dev with the 400gr lazers, I had inherited a load of the MTAC's and was using those.
Did you guys have any issues getting the 390 A-tips to shoot? If I shoot 3 shot groups 2 will always be touching and one about 1" away. Several different charges and seating depth from touch to .120" off.
I checked all fasteners and they are good. I actually swapped my scope last night in hopes that's my problem.
I also loaded some solids to try as well as backing this load off farther than I have.
It was shooting 350 SMK's FF loads into about 1/2"
I checked all fasteners and they are good. I actually swapped my scope last night in hopes that's my problem.
I also loaded some solids to try as well as backing this load off farther than I have.
It was shooting 350 SMK's FF loads into about 1/2"
Nope.... very consistent..
Note... DT factory 375CT barrel has now just over 1300 rounds through it!! and It still shoots like this!! 2x "3 shot" groups and 1 x "5 shot" group at 110yds..
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My answer is yes I had a hell of a time getting them to shoot until I backed off the seating depth as Chronicled in the first page of this thread.
It also took me a little while to learn that the 50 BMG powders is where it’s at rather than the 350 class, which seemed like the likes of retumbo through RL 33.
When I switched from RL 50 to H50 BMG, I lost 100 ft./s but I can tell you that my accuracy and consistency is dramatically improved both on paper and at steel far down range.
I suspect this is why most of the guys shooting this in the king of 2 miles have settled upon H50BMG
I do think reloder 50 is still a close contender and I still load that for my buddy and I know a lot of guys in this thread are still using that
I personally don’t think that the primer or the case makes a heck of a lot of difference in terms of accuracy, but it may matter for velocity & standard deviation, which is a huge part of the equation past 1000 yards
Just my $0.02
It also took me a little while to learn that the 50 BMG powders is where it’s at rather than the 350 class, which seemed like the likes of retumbo through RL 33.
When I switched from RL 50 to H50 BMG, I lost 100 ft./s but I can tell you that my accuracy and consistency is dramatically improved both on paper and at steel far down range.
I suspect this is why most of the guys shooting this in the king of 2 miles have settled upon H50BMG
I do think reloder 50 is still a close contender and I still load that for my buddy and I know a lot of guys in this thread are still using that
I personally don’t think that the primer or the case makes a heck of a lot of difference in terms of accuracy, but it may matter for velocity & standard deviation, which is a huge part of the equation past 1000 yards
Just my $0.02
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@secondofangle2 @232593 and who ever else is willing to lend a brain I’ll link my thread here so I don’t derail this one any farther since it’s not a Cheytac
www.snipershide.com
375 RUM- Gibbs (Box Monkey Express)
I got the idea from 375 ultra mag thread. I decided to do a 375 Rum with a 40* shoulder, moved ahead .053" and taper reduced to .006" A guy over on that forum had done a similar cartridge several years ago and called it the 375 Box Monkey Express. Initially I tried to seat the bullet hard into...
www.snipershide.com
I also have a tangential question for advice: I'm getting a new barrel from E-ST soon, using a brand new reamer I bought for consistence of chamber over subsequent builds (wish I had done this sooner). If it's a shooter, I'm going to get custom made WTC dies for it. So, I need to decide on brass, either Bertram or Peterson, since I'll probably have $2500 in the die set.
I'm inclined to finally jump off the Bertram train (even though I have 150 used and 150 new pieces) and onto the Peterson train because, looking into the future, in the USA, I'm guessing Peterson will be a more reliable/consistent supplier of this brass, AND resale value may be better if everything is built around the most popular brass (meaning, I have the reamer that makes the chamber that makes X Brass match this custom reloading die).
The goal here is to futureproof something I'm going to have several thousand dollars wrapped up in (the carbide reamer was almost $500).
Thoughts?
ETA: I just talked to Dan Warner and he said Peterson. So I guess that question is pretty much answered.
I'm inclined to finally jump off the Bertram train (even though I have 150 used and 150 new pieces) and onto the Peterson train because, looking into the future, in the USA, I'm guessing Peterson will be a more reliable/consistent supplier of this brass, AND resale value may be better if everything is built around the most popular brass (meaning, I have the reamer that makes the chamber that makes X Brass match this custom reloading die).
The goal here is to futureproof something I'm going to have several thousand dollars wrapped up in (the carbide reamer was almost $500).
Thoughts?
ETA: I just talked to Dan Warner and he said Peterson. So I guess that question is pretty much answered.
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Peterson brass in 375 cheytac is like Lapua in 6ppc.
The standard 375 reamer here runs $220 and the advantage to owning your own is in not having to re-do the learning curve with each new barrel.
I am running 4.240 with the A-tips and H50BMG.
The standard 375 reamer here runs $220 and the advantage to owning your own is in not having to re-do the learning curve with each new barrel.
I am running 4.240 with the A-tips and H50BMG.
This is the exact answer I was looking for. Gonna order a 1:8 Thanks
If you are getting a new barrel get slower than 1:8 twist if possible. My first barrel was 8 twist without issues but that's flirting with the edge.
I've been playing with some solids also so I'm gonna go 1:8.
My MV is a bit lower than what you guys are running also.
After blowing up 9 bullets in a row st 3014 in 1-8 twist I advise you to go to minimum 1-9.Perfect
At 2950 in a 1-8 twist you're already about 10,000 too fast RPM.
I also gave 2 friends running 390 A Tips in a 1-10 and kicking ass out to 4227 yards.
The formula if you don't know us Velocity times 720 divided by barrel twist.
I learned a gard lesson in a 1-8 with A TIPS abd had to go to Cutting Edge Solids .
When you go past 255,000 RPM you're in danger zone.
Ask Shane Bryan or Jaclyn.Thry also run the 390 A Tips.
You might get away with it for a short time in a new barrel but when fire cracking starts or and scratching of bullets at 2950 RPM in a 1-8 they will
come apart.
I learned it the hard way in an ELR match.
Good Luck.
Thanks for the input.
I have a 1:9 now and have fired some solids and seems to work but haven't taken the solids into trans yet I was going to go 1:8 because cutting edge recommends 1" faster for going through trans and I wanted to try some of the 400gr lazers also.
Haha thanks. This is Shane by the way. Jaclyn and I both ran 1:10.5 this year with great success. My first barrel was 1:8 without issues but it would definitely right on the edge @3000fps.
