375 Raptor, thoughts and opinions

[Dragster]

I looked at tbe 375 raptor recently, but no barrels, no dies, were in stock readily available. Plus 375 bullrts were expensive for a pinker...so I went with the 358 win in an AR...loaded up a variety of bullets readily available. Even several varieties of 9mm 147 Gold Dot & 147 HST....350 legend 250 gr SubX, 350 legend 160 gr, plus a bunch of regular 358 bullets...all in necked up 14 cent ea. 308 brass...super fast, no trimming...homemade double bump mandrel go from .308 to ist bump .338 to 2nd bump .358 one press stroke with no loss of brass.
It'll shoot 9mm, 350 legend, and 358 dia all the way up to 310. Very versatile & inexpensive.

It took me most of the first half of 2022 to gather the dies and barrel but I was able to eventually get everything and build the rifle. As far as bullets go, I have a large supply as I also shoot a 375 H&H. That was what really dictated this build for me - I already had all the bullets and primers that I needed. I bought both a CH4D die set and a Lee die set and crimper die. It is a much more involved process to make 375 Raptor brass but it's not really that bad, it just takes awhile. I'm looking forward to developing this rifle for all my medium/big game hunting needs.
Your 358 Win sounds like a great way to go as well but like I said, I already had the components.
I will be developing loads from the 235gr Speer to the 300gr round noses and boat tails. I will be posting information on this site.

 

[Hausser]

Good morning,
I also have an X-Caliber barrel and experienced the same exact problem. My rifle is Aero Precision M5 based with an X-Caliber 18" barrel with carbine length gas system. After I was able to clear the jam and upon inspection of the cartridge, I could see clear rifling engraving on the bullet. I'm loading Speer 270gr SPs with Vihtavouri N530 and loaded them to the recommended COAL listed on 375 Raptor's web page (2.790"). My fix has been to shorten the COAL so that the cartridge smoothly chambers and comes to full battery. I ended up with a COAL of 2.760" as reliably feeding in my rifle. It just seemed odd to me that the Barnes 270gr LRX, which is a longer bullet, would have a listed COAL of 2.725". What did X-Caliber have to say about the chamber and/or reaming of the chamber?

I ended up tearing the gun down and shipped the barrel in. They initially advised there was nothing wrong with the barrel, before I could finish describing the issues. After going back and forth over the phone, I was advised the barrel had been re-chambered with a previously unused reamer and should be all set. We'll see once my back allows me to start 'pumping the press'.

I know the post is over a year old, but 375 Raptor discussions are few and far between. As it turns out I just finished with my build... AR 308 (DPMS style) Frankengun with 24" X-Caliber 10 Twist. Instead of using 308 brass, I went with 358, so case mouth forming is even easier with much less stretching.
I've got some handloads ready to try out in the middle of next week, with initial emphasis on IMR4166 since it's less temperature sensitive than the powders listed on the 375 Raptor load site. The available load recipes are quite scant as well, so it's a work in progress. @ mac86951, did you pursue a build over the last year plus?

 

[TC260]

I ended up tearing the gun down and shipped the barrel in. They initially advised there was nothing wrong with the barrel, before I could finish describing the issues. After going back and forth over the phone, I was advised the barrel had been re-chambered with a previously unused reamer and should be all set. We'll see once my back allows me to start 'pumping the press'.

What problems were you experiencing?

 

[mike mccormick]

Steve Satern is a good one to talk to on this cartridge. Satern Barrels

 

[Orr89rocz]

I looked at tbe 375 raptor recently, but no barrels, no dies, were in stock readily available. Plus 375 bullrts were expensive for a pinker...so I went with the 358 win in an AR...loaded up a variety of bullets readily available. Even several varieties of 9mm 147 Gold Dot & 147 HST....350 legend 250 gr SubX, 350 legend 160 gr, plus a bunch of regular 358 bullets...all in necked up 14 cent ea. 308 brass...super fast, no trimming...homemade double bump mandrel go from .308 to ist bump .338 to 2nd bump .358 one press stroke with no loss of brass.
It'll shoot 9mm, 350 legend, and 358 dia all the way up to 310. Very versatile & inexpensive.

Wait so it can send .355 bullets down .358 tube no problem? Interesting

 

[Dragster]

I ended up tearing the gun down and shipped the barrel in. They initially advised there was nothing wrong with the barrel, before I could finish describing the issues. After going back and forth over the phone, I was advised the barrel had been re-chambered with a previously unused reamer and should be all set. We'll see once my back allows me to start 'pumping the press'.

So, I shot my AP/XCAL 375 Raptor today. Wasn't trying to sight it in nor even check velocity. I just wanted to be sure that it fired and operated correctly. My loads were VV N530 from 43gr to 44.6gr w/Speer 270gr SPBT, CCI 250 primers and a COAL @ 2.760" I had to back them off from the published 2.790" to get them to feed. Published loads from 375raptor.com for above bullet powder combination but I did not change powder charges even though I seated the bullet 0.030" deeper into the case. I loaded 3@43gr, 3@43.5gr, 3@44gr, & 3@44.6 gr. None of these loads showed any signs of over pressure in my rifle. I was only shooting at 50 yds but except for the very first shot from my never fired, cold barrel, the other 11 rounds were a 1" group. I'm pleased with the accuracy and the fact that there are no over pressure indications. Recoil was moderate but (for me) no big deal at all. Tonight I'm loading some more of the above combo but doing 10 rounds at 43gr so that I can tune my gas system as it is currently fully open and cycling the BCG extremely fast. Once I get the gas system/buffer system tuned to these loads, then the fun begins with finding max velocity, max accuracy, etc. for this combination.

*The above information is informational only and is not meant nor presumed to work in any other rifle except for the one that I own. Use information at your own risk.

 

[Dragster]

Has anyone loaded 375 Raptor in H322? I can't seem to find any RL 10X nor RL1200 and the H322 falls right between them in the relative burn rate chart. Any reason I couldn't start with the RL 10X data from 375raptor.com?

 

[Ray123]

Wait so it can send .355 bullets down .358 tube no problem? Interesting

Yep, got a bunch of plinkers loaded up. And you can go the other direction with the 450 Bushmaster resize all the heavy .458 bullets to .452 and shoot 400 gr and 500 gr bullets in the 1- 16 twist Bushmaster barrel subsonic so it meets the 458 socom standards with really heavy bullets... (don't know if they stabilize in a 1-24 twist.)
This makes the 450 Bushmaster more versatile and much less expensive option than the socom with cheap pistol bullets for plinking, and a bit more range with lighter bullets and able to handle the same large bullets in subsonic mode...if you so desire...resize 45-70 ,or 458 mag bullets...use sizing lube.

 

[ShadowAviator]

I don't really have much to add. I am waiting on my 375 Raptor barrel. I am gonna rebarrel my Tikka with a 18" barrel. I went with Mos-Tek instead of xcalibur.

I bought a Lee die set in case CH4D didn't make enough, but they did, so I now have both.

I picked up some 358 WIN brass to form 375 Raptor. I need to get a little chopsaw to make trimming easier.

As far as bullets, I picked up some 270gr Speers because they are cheap. However the projectile I am eager to try is the 230gr Peregrine VLR4. Its a monometal. I read about someone else using this bullet in the Raptor and was getting 2500fps from a 18" barrel. I don't know if that was max, or could be pushed higher. According to the 375 Raptor website, they were getting 2575fps with the Speer 235 and TSX 235. So hopefully I can get the Peregrine closer to 2600fps.

Let me know if you want more info on the Peregrine.

In the image below: 168gr SMK (.308), 270gr Speer (.375), 230gr Peregrine VLR4 (.375)

 

[Rat Rifle]

I LOVE those Heavy, Slow bullets. But for now, My 358 Winchester and My 444 Marlin will have to foot the bill

 

[Hausser]

What problems were you experiencing?

I assembled ammo using different combinations per the load data provided on....

https://www.375raptor.com/load-data/

Some of the combinations would not chamber and had rifling marks after getting the rounds unstuck. In my opinion, there wasn't enough freebore

 

[Hausser]

Has anyone loaded 375 Raptor in H322? I can't seem to find any RL 10X nor RL1200 and the H322 falls right between them in the relative burn rate chart. Any reason I couldn't start with the RL 10X data from 375raptor.com?

I picked up 10X at Powder Valley a couple weeks ago.

 

[Geno C]

I’m going to be doing something similar. Full length 308 case though to skip the trimming. Mag fed out of a LA bolt though.

 

[Ray123]

I’m going to be doing something similar. Full length 308 case though to skip the trimming. Mag fed out of a LA bolt though.View attachment 1404414

I already been doing that for a couple years...308 LA 30" barrel 8 twist 3.4" cartridges out of the magazine...but I was sticking with 30 caliber
, supersonic not subs. Shot a few subs just for fun. But it shines with 200 gr SMK at 2856 fps ave .715 bc and 225 eldm at 2675 fps and .777 BC the slightly higher 230 gr at 2620 fps. Got some 250 Atips but was thinking super sonic...seems like a waste to shoot them at 1000 fps.
I can run resized 500 gr 458 out of a 16 twist bushmaster with alot of subsonic energy inside 200 yds to up close where most would use them, inside 70 yds for hunting...been playing with the 8.6 blackout, waiting on a chronograph for the 300 gr Bergers...the 3 twist barrel has already destroyed a muzzle brake and the chronograph bayonet...1400 fps 285 eldm don't make it to the 50 yd target...have some pure copper to try without the chronograph & brake...so far it's only a subsonic gun with lead bullets, and the limiting 3 twist. The 450 bushmaster is more versatile runnung both subs and supers with ease...haven't given up on the 8.6 blackout ...yet ...I even asked Faxon about buying an 8 twist...the barrel maker said, "no"..."it's under license agreement." A 3 twist is all ya get...too limiting, ya can't trust lead core bullets above 1000 fps to make it to the 50 yard target or destroy your muzzle devices.

 

[Geno C]

I already been doing that for a couple years...308 LA 30" barrel 8 twist 3.4" cartridges out of the magazine...but I was sticking with 30 caliber
, supersonic not subs. Shot a few subs just for fun. But it shines with 200 gr SMK at 2856 fps ave .715 bc and 225 eldm at 2675 fps and .777 BC the slightly higher 230 gr at 2620 fps. Got some 250 Atips but was thinking super sonic...seems like a waste to shoot them at 1000 fps.
I can run resized 500 gr 458 out of a 16 twist bushmaster with alot of subsonic energy inside 200 yds to up close where most would use them, inside 70 yds for hunting...been playing with the 8.6 blackout, waiting on a chronograph for the 300 gr Bergers...the 3 twist barrel has already destroyed a muzzle brake and the chronograph bayonet...1400 fps 285 eldm don't make it to the 50 yd target...have some pure copper to try without the chronograph & brake...so far it's only a subsonic gun with lead bullets, and the limiting 3 twist. The 450 bushmaster is more versatile runnung both subs and supers with ease...haven't given up on the 8.6 blackout ...yet ...I even asked Faxon about buying an 8 twist...the barrel maker said, "no"..."it's under license agreement." A 3 twist is all ya get...too limiting, ya can't trust lead core bullets above 1000 fps to make it to the 50 yard target or destroy your muzzle devices.

You wouldn’t happen to have that 375 reamer, would you?

 

[Ray123]

You wouldn’t happen to have that 375 reamer, would you?

No, but 4d reamer rental, probably has one with a go gage too..
I looked at the 375 raptor but decided against it, for now ...and went with the 358 Win. In the AR 10, less expensive and similar performance with 250 vs 270 gr in supers. And I have the 8.6 blackout for long range, the 300 gr Berger as far as you'd want to shoot subs. For close range energy the resized 500 gr bullet stablize in 450 bushmaster 16 twist.