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.375 Raptor

Yes, I just started. Winchester new brass, CCI large match primers, Speer 270gr sp, N530 43 gr 2.805 OAL. Pressure fine. Didn’t crono. Trying 44gr next time.
 
Hello to all,
Reviving this thread since it's been many months since last post here.
I just finished building my AR 375 Raptor with 10 twist 24" barrel. I'm also looking for some load information.
Any new developments to share? Thank-you. H
 
I built a 375 Raptor with a 22" X-Caliber heavy barrel and JP. Enterprise silent capture recoil sys. I have used both 308 brass and 358 Win brass. To me it seems a little easier, 1 less step using the 358 Win brass. I expand the 358 Win brass with an expander die then put it through the sizer die. Trim the brass using the Forster power case trimmer and a drill press, then final trim with a Lee Power Quick Trim Case Trimmer and Lee Quick Trim die.
Disclaimer: Use any reloading information at your own risk: Not responsible for accidents, accidental injuries or death. Reloading is dangerous and can cause serious bodily harm or death.
I have a starting load in which I use 37.0gr of H4895, and it seem to work fine,the case is fairly well filled when loaded with Speer's 270g SP.
Posted: 9/30/21
 
Thanks 11.
Were you able to run 'em over a chrony?
I prefer resizing the 358 brass as well. If in the future you can't find it, check out BACO (Buffalo Arms Co) where I was able to find it a couple months back. They often have hard to find items and not just for Black Powder use. I have Sierra Gameking 250s and 300s as well as the Speer 270s sitting on my loading bench. Got a bottle each of jug of IMR 4166 Enduron, H322, and H4895 powders. Will begin experimenting this week if weather permits.
 
It has been a while since I have been to the range and shot my 375 Raptor, but if my memory serves me correctly, the velocity of the 270gr Speer's, using 37.0gr of H4895 was a little under 2000fps. Don't quote me on that because it has been a while and I don't think I wrote it down at the time.
I do have some other loads ready to chrono but just haven't had time to go do it yet.
For me the 37.0gr load was shooting pretty accurate and was easy on my LR-308 and shoulder. Consistantly hitting 4" steel at 100yds. (as load development continues, will work on getting a little higher velocity and tighter groups)
Disclaimer: Use any reloading information at your own risk: Not responsible for accidents, accidental injuries or death. Always start with lower weight and work up slowly. Reloading is dangerous and can cause serious bodily harm or death.
 
Just finished loading 0.5 grain incremental samples from 37 to 42 grains IMR 4166 using Sierra Gamekings in 250 and 300 grains as well as Speer BT Soft Point in 270. Planning on range time middle of next week and will start low and work up. Keep you posted..
 
I have looked at this for maybe replacing my Ruger 375 when hunting black bears over bait. When I compare muzzle velocity data between the with comparable barrel lengths the difference is ony about 200 fps. At ranges that present themselves for baited bear I don't think the bear would notice the difference,

I use Hammer bullets and I am pretty sure that I would still get two holes with the Raptor, but with a little less recoil. I have a new production CRF Win 70 in 308 sitting waiting for an idea on what to build with it and maybe a short range bear gun in 375 Raptor is the build.

I realize you don't need a 375 to hunt black bears but I like the idea that with the proper bullet I can get two holes in any bear. Two hole is good, two big holes is better.
 
Just a little side note here: Thought I could type this up in "Word" then copy and paste, well lets just say that it didn't look right when I did. So it had to be typed in directly, oh well....
On Saturday, March 26, 2022, I finally got to the range and with the CED-M2 chronograph I was able to get a little bit of data.
Elevation: about 150ft: Barometric pressure: unknown, Temperature: upper 60's low 70's. and the chronograph was about 12ft from the muzzle.
Rifle DPMS LR/SR style lower and matching upper from "Precision Tactical".
Cartridge: 375 Raptor, custom heavy contour X-Caliber barrel.... X-Terminator muzzle break and rifle length gas port with adjustable gas block, JP. Enterprise Silent Capture Buffer Spring, 15"M-Lok hand-guard.
See one of my previous post regarding forming 375 Raptor Brass.
From my prospective, the rifle shoots pretty good, easily hitting 4" steel targets at 100yds.
Just a few raw numbers from the chronograph using different powder charge weights.
Powder: H4895, Bullets: Speer 270gr SP.
Note: Data in the table below "Post with no spaces between the numbers, as opposed to looking correct with correctly spaced columns before posting????
For all groups: velocity in Feet / Second
37.0gr 39.0g 41.0gr
Group 1 Group 2 Group 3
1. 1879 1989 No Data
2. 1877 1957 2069
3. Error? 1945 2091
4. 1816 1967 2082
5. 1765 1978 2083
6. 1892 1959 Error?
7. 1680 ? Error? 2066
8. 1774 1968 2030
9. 1840 1961 2066
10. Error? 1948 2076
(note: most of the error's or missing data was user error...)

Disclaimer: Using any of my reloading data is at your own risk: NOT responsible for accidents, accidental injuries or death, nor for any damage to any firearm. Always start with lower weight charges and work up slowly. *** Reloading is dangerous and can cause serious bodily harm or death.
 
Thanks 11.
Were you able to run 'em over a chrony?
I prefer resizing the 358 brass as well. If in the future you can't find it, check out BACO (Buffalo Arms Co) where I was able to find it a couple months back. They often have hard to find items and not just for Black Powder use. I have Sierra Gameking 250s and 300s as well as the Speer 270s sitting on my loading bench. Got a bottle each of jug of IMR 4166 Enduron, H322, and H4895 powders. Will begin experimenting this week if weather permits.
Hi Hausser,
What did you come up with for load data using the H322?
 
I’m still waiting for my X-caliber barrel. I’ve only started processing brass. I’m using new starline .308 brass and after trying to one step size it with a FL size die I have since switched to a two step neck sizing process before FL sizing and it feels a lot less like I’m overworking the brass in one step. .308-.35 neck size then .35-.38 neck size then FL size. The best investment I’ve made for processing brass is the Little Crow case trimmer with .375 raptor insert and I grabbed a .300 BLK insert too. It fits in a standard 1/2” drill chuck and makes short work of case trimming. I will be working with H322 for 270gr supers as I have 32 LBS of it from my mk262 clone development. Now if I can only find some 350 MK or some 400gr Makers subs….
 
I’m still waiting for my X-caliber barrel. I’ve only started processing brass. I’m using new starline .308 brass and after trying to one step size it with a FL size die I have since switched to a two step neck sizing process before FL sizing and it feels a lot less like I’m overworking the brass in one step. .308-.35 neck size then .35-.38 neck size then FL size. The best investment I’ve made for processing brass is the Little Crow case trimmer with .375 raptor insert and I grabbed a .300 BLK insert too. It fits in a standard 1/2” drill chuck and makes short work of case trimming. I will be working with H322 for 270gr supers as I have 32 LBS of it from my mk262 clone development. Now if I can only find some 350 MK or some 400gr Makers subs….
Please let us know what you find out for H322 loads. H322 looks to be within +/-5% of Alliant 10X and I cannot find any 10X but I do have H322. I will also be working up loads and will publish them here. Thanks!
 
Question for you. This winter I plan on starting to reload for my Raptor. I have a ton of primed military 7.62 brass. Any reason I can’t use that?
 
First, my 375 Raptor is a 12" barreled (X-caliber) pistol in a Defiance anTi action and Black Collar Pork Sword chassis.
I am using Peterson Match .308 brass neck expanded to .358 then to .375, and then full length sized and trimmed. I formed 500 cases; once I have shot them and they are fire-formed I will anneal the necks. So far between forming and load development, I haven't had any case splitting issues.

@gjb89, what type of load do you plan on running, subs or supers? What grain weight?

I initially bought a bunch of 270gr Speer (very accurate!) but eventually decided on Maker 400gr for subsonic and Maker 190gr Tipped T-Rex for supersonic.

270gr Speer with 37.3gr of IMR 4198. This gave just under 1800fps and was a very accurate load for me.
The same bullet with 44.0gr of H-335 was just over 1800 fps and had a huge fireball. This was also very accurate. Caution, Both of these are close to max loads!!

400gr: 18.3gr of IMR 4227 gives me an average of 1087fps, 17.2gr of 4227 gives me 957fps. Both of these are at accuracy nodes. I am interested to see how much difference in velocity with the 18.3gr load in the hunting season cold weather!

190gr T-Rex not yet tested.
 
Thanks for the info as I have maker 400s, 350s, & 190s. I also have some 300 grain PPUs that I'm thinking of an economical plinking sub round. I have a 16" barreled action (Origin with Black Collar barrel), chassis and seating die on order. Also, have an AB Raptor 10 still in jail. Just forming cases in the mean time. It's nice to see new data as much of the 375 Raptor data's components are unavailable or no longer made. Are you using Gordon's Reloading Tool?
 

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