Building an interesting little 338 RCM

[atl5029]

This is interesting. Tagging to see result's. Make sure you have a long enough mag and a throat that uses the magazine.

Would love to hear the logical path of slow monos at high twist rates equals good perfromance. That seems counter-intuitive, but following intuition alone would have stopped most breakthroughs in technology.

Where will you ever find brass? If you find it, it will surely be on sale! These rifles were like 50% off at CDNN a couple years ago.

Better get Quickload to help you guess what bullet.

my only concern is the throat. Should be able to seat em long cause its a Mauser action, but not sure how close bullets will be to the rifling. A custom throat wasn't an option i was thinking of but i should have been. I can probably have my smith lengthen the throat with a reamer if it becomes a problem. More of a concern for target bullets though, as the CEBs are bore riders. And I've found brass. Seems like they just did a run cause all my product notifications came in lol. Got 150 but should probably buy a few more

Following. This kind of reminds me of the new "8.6 BLK" cartridge but a magnum version. Something my mind automatically jumped to when I read about the 8.6 BLK. "Neat, but I'd need more speed"

8.6 BLK (blackout) is a .338 that uses 6.5 Creedmoor brass as the parent cartridge (shortened). Barrels are 1:3 or 1:4 twist rate. It'll run subsonic and supersonic ammo.

I'm all over the new 8.6. I want one of those too in a 12" configuration. Waiting on Faxon to release barrels and I'll have one. They're 1:3 twist. Been following development of that cartridge since i first heard of it. 12" Barrel with a 160 Barnes will give you 2250 fps but its spinning so insane fast that when it opens it'll be devastating.

 

[atl5029]

Loaded a few dummy rounds to check feeding once my rifle is done. Those are 250 grain PPU OTM with the base seated right at the shoulder/body junction. End up being pretty long but fits in the Mauser magazine perfectly.

 

[Royal Knight]

I have a want for the little 338 rcm as well. I have some brass an bullets. Going to use a Defiance action. Not settled on a barrel yet. Maybe a #3 at 22"

 

[Left Hand Dave]

I have considered this for a pistol build but started looking at the 325 and .338-.300 WSMs instead due to brass availability issues.

 

[Royal Knight]

I have 100 pcs of brass and don't shoot all that much once I get a load figured out. I agree though the wsm vase has more capacity but it's been tough to find it too for me.

 

[ARlife4me]

I think the 338rcm is a good short cartridge and wouldn't mind have the 300rcm over the 300rsaum or the 300wsm.

 

[PusherX11]

View attachment 366000Loaded a few dummy rounds to check feeding once my rifle is done. Those are 250 grain PPU OTM with the base seated right at the shoulder/body junction. End up being pretty long but fits in the Mauser magazine perfectly.

Did you seat at the base of the boat tail, or base of bearing surface/beginning of boat tail? What's your COAL?

 

[dogz]

Many moons ago, I had a 338/300 WSM with a 21" barrel. I did a lot of work with it using 180's to 250's...neat little round but in the end I found it didn't do anything that most all other rounds don't already do.

I underforstand the shorter barrel wish but it's going to be at a cost. IE speed.........course we all know that we can make a cartridge run whatever speed we wish to justify if it means enough to us

Have fun

 

[atl5029]

It has been more than a few months, but the barrel and feed work is done and my little beast is back together. Looks pretty mean I think. Now just to decide on a scope. I'm currently back and forth between the Vortex Razor HD LHT 4.5-22x50 FFP, and the Athlon Ares BTR Gen2 4.5-27x50 FFP. Similar features all the way around, except on expert voice the Athlon is about half the cost. This is a hunting rifle after all, so is gaining 5x on the high end and saving about $550-600 bucks worth the 5.6oz lighter Vortex? Can anyone comment on the difference in glass between these two or anything else I'm not seeing?

 

[atl5029]

Following. This kind of reminds me of the new "8.6 BLK" cartridge but a magnum version. Something my mind automatically jumped to when I read about the 8.6 BLK. "Neat, but I'd need more speed"

8.6 BLK (blackout) is a .338 that uses 6.5 Creedmoor brass as the parent cartridge (shortened). Barrels are 1:3 or 1:4 twist rate. It'll run subsonic and supersonic ammo.

Not wanting to hijack my own thread here, but while we are talking fast twist 338s, Martinakl, I told you I was on that 8.6 Blk train too, and it is awesome. Not at all long range but this gun is too handy and fun not to use a lot! And the fast twist does insane things to animals.