338 or .375 AM

[snox801]

Alright guys I ordered a 338 Am from Kirby going on two years now. As the time nears for the final emails to figure out exactly what I want I started second guessing my choices. I decided on the stock and everything else I told Kirby I want the baddest long range hammer he could make. Weight and cost are not the issue. I will only be using this gun for extreme long range. So weight is no issue and I have a 338 lapua build as close as possible in feel for practice.
So if I want the baddest long range hammer what would you choose and why. Or pros and cons. I wanna do this right the first time without second guessing. I know both guns can outshoot me but I may get there in time. Thanks for you insight.

 

[sp6x6]

Kirby would seem to have great input.Joe Russo on here shot a 3.8 inch group at 1680 yrds with a 338 Big baer,he might chime in .He shoots real loooooong

 

[RockyMtnMT]

I am excited about the .375. I will be building one on the .338 Lap to shoot a 400g bullet that we designed for a 9" twist. Anticipating 2900fps with crazy bc. Makes a 2000y rifle all day long.

Steve

 

[royinidaho]

With folks like Steve coming up with heavier than 350 grain offerings things definitely swing in the direction of a super hooty 375. Other wise the only advantage of a 375 AM over a 338 AM is 50 grains.

The 350 SMK is simply not enough bullet to bring the big 375 into its own.

I'm not able to stabilize 350/377 CEBs beyond a point somewhere between 628 and 980. Thus I've resorted to converting the SMKs to 353 grain brass pointed which increases bc significantly. Like 42" less drop at 1681 yards from an independent tester.

Since I began exploring with US-869 the 350/353 grain offerings are loafing along at slightly under 3300 fps MV. I was in the final stages of testing when the scope went south for the rest of the winter.:roll eyes:

Example of ES for a 3 shot group were 3278/3278/3276. Pretty darn good considering Retumbo resulted in too high of pressures at 3225 but the 869 groups and ES in the high 40s. Groups were the pitts however.

With a very slight tweak of seating depth the next 3 shots gave the same group size and 3323 fps average with single digit ES.

Got up to 157 grains of H-50 BMG with similar velocity and very low pressure and an enticing group when the scope went wonky. It's at Leuy at the moment.

My experience tells me that a 350+ grain offering moving along at 3200+ w/0.5 MOA or less consistency makes a fell wanna leave everything else in the safe.

Also I've got the big girl to under 16 pounds and it's still a pleasure to shoot.

Either cartridge will do what needs to be down, in fact, both cartridges are over kill except for possibly UFOs. I can almost guarantee that if you go with the 375 you'll never yearn for something bigger.

 

[snox801]

Thanks guys that was my thought process actually. Was set on the 338 but as these bullets keep coming along I keep feeling like the .375 might be better. I'm gonna go with a twist rate that can handle only the heaviest in whichever cause I'm not making the same mistake twice letting the smith choose, that's what lead me Kirby not getting what I wanted from the last one I won't go into that. But I feel if I do it this way when they come out with newer heavies or loooong copper ones. I haven't heard from him in a long time but the last time we talked he said he would be in contact with me to finalize everything. I hope this means caliber as I still have posts of question for him. Good news is I'm not in a huge hurry so he may be able to change caliber for me. Thanks again guys if only I had found this site sooner I would have saved a bunch of money.

 

[LR3]

I have a 375 AM that is great. Best long range group was 6 rounds into 12" at 2200 yds. As you can see both Royinidaho and I love our 375. I ve taken deer to 805 yds but it is certainly able for longer distances. The SMK has performed fine for me on deer and elk. My guess is it's frangible. However I asked Kirby to build me a 3000 yd rifle so he built me a 338AM. I ve seen the pictures of it and he s doing the long range testing and drops. I know there are mixed results with the 300gr Berger but that to me is plus for the 338. I m looking forward to comparing them.

 

[snox801]

Please keep me informed on which one is better in your opinion. I kinda got the same answer from Kirby also. I said I wanted the baddest long range rig and he was talking 338. But to be honest we have not been in contact a whole lot. We talked a bit and but when he said he would contact me to finalize it I felt better and no need to contact after that. Just makes his email load more. Lol.

 

[HARPERC]

,,,,,,,,,I am excited about the .375. I will be building one on the .338 Lap to shoot a 400g bullet that we designed for a 9" twist. Anticipating 2900fps with crazy bc. Makes a 2000y rifle all day long.............Steve

Bullets are most always the answer-there's yours! Go for it, you already have a .338 Lapua.

 

[snox801]

Bullets are what got me thinking. If comparing 300gr 338 to 350gr .375 they are so close. But as more companies make more high bc .375's like cutting edge 400 gr. I gotta think that that is the better way to go in the future. I really wanted to shoot the eld in my 338 so maybe hornady makes a .375 400gr eld. Or maybe a 300gr + lead core. Any idea why they all stop at 300 gr ? Still at a loss for what to do. Not sure if the long copper cutting edge would be the way to go cause it could over do it in the twist department for any other bullet if that one didn't work out. That has me leaning toward 338. But an not so long lead core .375 400 gr round would be amazing.

 

[snox801]

I am excited about the .375. I will be building one on the .338 Lap to shoot a 400g bullet that we designed for a 9" twist. Anticipating 2900fps with crazy bc. Makes a 2000y rifle all day long.

Steve

Sorry I didn't mention your bullet as the twist rate looks like it would be right where it should be. Is this one of the bullets Kirby is testing for you? I'm leaning the way of the 375 because of this. I also just heard from Kirby and he didn't help me any. Lol he said the new bullets may be changing things for the .375 so I'm still left wondering. Luckily I have a bit of time.

 

[RockyMtnMT]

Sorry I didn't mention your bullet as the twist rate looks like it would be right where it should be. Is this one of the bullets Kirby is testing for you? I'm leaning the way of the 375 because of this. I also just heard from Kirby and he didn't help me any. Lol he said the new bullets may be changing things for the .375 so I'm still left wondering. Luckily I have a bit of time.

The bullet that we have made that has me wanting a new barrel is 393g. I would not call it a super high bc type bullet. But should be a very accurate easy to use thumper. Just because of the weight the bc will be pretty high. We can take it longer and leaner in design. We will be doing this with most of the cals. It will render many single shot, which really does not matter to most long range guys. Not that difficult to hand load the next.

Steve

 

[snox801]

I guess that's what I'm trying to decide. I have a action with mag as a repeater, but that seems like a waste now if I choose to go with a long copper and render it a single shot. Not that big of deal cause I simply want the best long range capability.

 

[TXAoudadKlr]

I'll be looking towards a 375 for my next build as more bullets for it become available in the coming years if they don't pan out a big 338 will get the nod.

 

[snox801]

I'll be looking towards a 375 for my next build as more bullets for it become available in the coming years if they don't pan out a big 338 will get the nod.

That's my problem mine is gonna be done so do I gamble and go .375 or stay with .338. I mean if hornady comes out with a 300 gr plus eldx it would be really sweet.