338-06 AI & M70 Questions

H

hseII

Beginner
Jul 26, 2016
116
2
Hello,

I'm wanting to build a long throated 338-06AI.

•Left Hand M70 CRF Clone Long Action
• 26" barrel.
• Some sort of hunting weight Composite Stock
• Wyatt Extended Bottom Metal

I'm curious to see what the best possible performance may be.


Looking at the SAMMI specs on the 338-06 A Square, the COAL is 3.440".

If we take the Length of the 200 grain AccuBond @ 1.340".

3440"
-1340"

2.100"

2.100" +
1.700" Nosler AccuBond LR 265 grain
3.800"- This has to be Too Much: that's longer than a Lapua.

1.700
1.340

0.360" delta. I suppose we can't do that because 3.800" is too long.

As an area fills up, the pressure increases, right?

So if by long throating, the area enlarges?

Where is the point of vanishing returns?

3.500"?
3.550"?
3.600"?

I'm sure you're thinking by now, "Why doesn't this guy just buy a .33 Nosler, or a Lapua & be done with it?

Easy.

0.473" vs. 0.588"

Well why not just buy a Winnie & be done with it?
That was actually my 1st thought, but that's 0.473" vs. 0.532".

The short answer is 5 > 3.

So,

If loading the 338-06AI to maximum Long Action Lengths, with the Wyatt extended magazine feeding it, what's the longest I can go, & it work every time?

How do you wizards know how far is far enough?

Thank You Ahead of time for Your Input.
 
While my first thought is "Why?", my second thought is "because you can and because you want to".

I cannot speak to the issue of long throats as I am not knowledgeable enough to discuss it or even think of recommendations. I would suggest talking to some gunsmiths that have done this work before, and seeing what they recommend. Cooper firearms builds rifles in the 338-06AI; might be worth calling them.

In talking to those who have 338-06AI's in this area, I have found that for the extra expense of the dies and time in the process of fire forming brass and finding a good load for their AI version, ( learning this myself with my 250AI) they are not getting any gains in velocity over what I am getting in my 338-06. Perhaps I have a faster barrel? Not sure.

Just know that I am happy with how it shoots the Wby factory ammo, 210 gr Partition at 2750 fps and 1/2" groups at 100 yards, and my hand load with the Sierra 215 gr GK, I am getting the identical velocity and accuracy. And with the higher BC of the SGK, this loads surpasses the 210 gr Partition 338 Win Mag factory ammo at 300 yards.

Good luck in your search for your answers and your project. Keep us posted, as I would like to know what you learn!
 
Blkram":1o71hkb7 said:
While my first thought is "Why?", my second thought is "because you can and because you want to".

I cannot speak to the issue of long throats as I am not knowledgeable enough to discuss it or even think of recommendations. I would suggest talking to some gunsmiths that have done this work before, and seeing what they recommend. Cooper firearms builds rifles in the 338-06AI; might be worth calling them.

In talking to those who have 338-06AI's in this area, I have found that for the extra expense of the dies and time in the process of fire forming brass and finding a good load for their AI version, ( learning this myself with my 250AI) they are not getting any gains in velocity over what I am getting in my 338-06. Perhaps I have a faster barrel? Not sure.

Just know that I am happy with how it shoots the Wby factory ammo, 210 gr Partition at 2750 fps and 1/2" groups at 100 yards, and my hand load with the Sierra 215 gr GK, I am getting the identical velocity and accuracy. And with the higher BC of the SGK, this loads surpasses the 210 gr Partition 338 Win Mag factory ammo at 300 yards.

Good luck in your search for your answers and your project. Keep us posted, as I would like to know what you learn!
Click to expand...
Thank You.
 
I'd think the simple answer is magazine length unless you want a single shot.
If you're using a 3.6" mag then anything throated beyond that could perhaps be wasted or worse, make mag length loads shoot poorly.
Your rifle of course, but I'd build a few dummy rounds mag length minus ? And see if that gets what you want.
 
Dwh7271":2og695wt said:
I'd think the simple answer is magazine length unless you want a single shot.
If you're using a 3.6" mag then anything throated beyond that could perhaps be wasted or worse, make mag length loads shoot poorly.
Your rifle of course, but I'd build a few dummy rounds mag length minus ? And see if that gets what you want.
Click to expand...

My old 300WM used HS-Precision RUM mags, & worked wonderfully.

I suppose I could go that route again, but I don't want a detach mag this time.

I was hoping someone had already determined the max COAL using the Wyatt's.

Looks like that will be my 1st step.
 
hseII":1xr9n3sn said:
Dwh7271":1xr9n3sn said:
I'd think the simple answer is magazine length unless you want a single shot.
If you're using a 3.6" mag then anything throated beyond that could perhaps be wasted or worse, make mag length loads shoot poorly.
Your rifle of course, but I'd build a few dummy rounds mag length minus ? And see if that gets what you want.
Click to expand...

My old 300WM used HS-Precision RUM mags, & worked wonderfully.

I suppose I could go that route again, but I don't want a detach mag this time.

I was hoping someone had already determined the max COAL using the Wyatt's.

Looks like that will be my 1st step.
Click to expand...

This is Wyatt box.

http://wyattsoutdoor.com/product_info.p ... ucts_id/36

What I do is get some bullets like to shoot and make up some dummy rds. Your also going to move lands forward. My 280AI,35 WhelenAI,30-338mag and 30-06,270,284 I had throated longer. I put 284 long action so when from 2.800" to almost 3.200" and that's with 180gr VLD.

When I move things forward I try keep bullet length in the neck from the new lands or if it's something like the Berger lands may start middle of the bearing surface.

http://www.bergerbullets.com/wp-content ... 3/COAL.pdf
 
30-338":1kc3a0cw said:
hseII":1kc3a0cw said:
Dwh7271":1kc3a0cw said:
I'd think the simple answer is magazine length unless you want a single shot.
If you're using a 3.6" mag then anything throated beyond that could perhaps be wasted or worse, make mag length loads shoot poorly.
Your rifle of course, but I'd build a few dummy rounds mag length minus ? And see if that gets what you want.
Click to expand...

My old 300WM used HS-Precision RUM mags, & worked wonderfully.

I suppose I could go that route again, but I don't want a detach mag this time.

I was hoping someone had already determined the max COAL using the Wyatt's.

Looks like that will be my 1st step.
Click to expand...

This is Wyatt box.

http://wyattsoutdoor.com/product_info.p ... ucts_id/36

What I do is get some bullets like to shoot and make up some dummy rds. Your also going to move lands forward. My 280AI,35 WhelenAI,30-338mag and 30-06,270,284 I had throated longer. I put 284 long action so when from 2.800" to almost 3.200" and that's with 180gr VLD.

When I move things forward I try keep bullet length in the neck from the new lands or if it's something like the Berger lands may start middle of the bearing surface.

http://www.bergerbullets.com/wp-content ... 3/COAL.pdf
Click to expand...

Thank You.
 
30-338 have some great advice as far as having the smith match the chamber to your intended Bullet. Just my assumption but a plain old M70 3.6" Mag box will give you a ton of room for nearly any Bullet you wanna run.

I would also go over what you want out of a certain Bullet and get an idea if you can get there with your cartridge.

Also, it isn't a big trick for a good smith to open up the bolt so you can fit a .532" case on it. Just some food for thought.
 
hse - I have thought about turning my Model of 1917 into a .338-06, or a .35 Whelen for the increased bullet weight and diameter.

It holds 6 in the magazine, is utterly reliable, and reasonably accurate.

But I hadn't worried about making into the "AI" version, or making the magazine & throat longer.

Regards, Guy
 
I know Rich Sherman is doing a 338 Sherman right now. It's a 338-280 Imp (not AI). Basically it's the max you can do on a .473 bolt face. I'm sure he will have some info on Long Range Hunting soon.
 
Go classy with the m17 guy, 9.3x62
3ac94d308c28e609dc386f96383ce108.jpg



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