Gunsmithing 300prc build

[Lindley Machine]

I'm new here sorry if I do this wrong.
I have a customer who bought a brownells MDT chassis long action for a rem 700, he wants a 300 prc from it but magwell is for 3.715 aics.
Brownells says it will work both with chassis and mags, but I'm having second thoughts, anyone out there ever tried to fit 300prc in the 3.715 aics mags?

 

[cast1]

It’ll work just fine. Do you have your reamer yet?

 

[Mk32784]

Disregard - see below

 

[gnochi]

I'm new here sorry if I do this wrong.
I have a customer who bought a brownells MDT chassis long action for a rem 700, he wants a 300 prc from it but magwell is for 3.715 aics.
Brownells says it will work both with chassis and mags, but I'm having second thoughts, anyone out there ever tried to fit 300prc in the 3.715 aics mags?

The 3.715 AICS mag has a COAL of 3.625” - you will *not* be able to run 300PRC at SAAMI COAL.

That said, I’ve talked to @MDT_OFFICIAL support about CIP-length support in the ESS/etc., and to quote them:

“At this time we do not plan to make a 3.850" cut into a 700 platform as the 700 itself cannot accept it. Their 338 mag is 3.775". That being said, we have had customers mill out the front of the mag well to make it happen with both of those lengths.” (Note: this was before the ACC was announced.)

So, mill out the front of the magwell by 0.135” and you should be good to go with the longer mags.

 

[Lindley Machine]

The 3.715 AICS mag has a COAL of 3.625” - you will *not* be able to run 300PRC at SAAMI COAL.

That said, I’ve talked to @MDT_OFFICIAL support about CIP-length support in the ESS/etc., and to quote them:

“At this time we do not plan to make a 3.850" cut into a 700 platform as the 700 itself cannot accept it. Their 338 mag is 3.775". That being said, we have had customers mill out the front of the mag well to make it happen with both of those lengths.” (Note: this was before the ACC was announced.)

So, mill out the front of the magwell by 0.135” and you should be good to go with the longer mags.

Thanks for the reply, I think I'm going to mill out for the 3.775 so I will only have to remove .06, do you see any issues of doing that. The ID of the of the 3.775 would be about 3.715

 

[Lindley Machine]

It’ll work just fine. Do you have your reamer yet?

No reamer, the customer has a criterion remage barrel, I've made a 6.5 Creedmore from one of these and the barrel is nice quality for 300$.

 

[MDT_OFFICIAL]

For reference as well, if you are using a factory Remington 700 to go to 3.850" you would also need to remove material from the feed ramp as well. This is why in most of our chassis systems for a Remington 700 long action, we go to 3.715," so it is a drop-in fit. The only exception is our ACC since most customers will use clone actions on that.

 

[Lindley Machine]

For reference as well, if you are using a factory Remington 700 to go to 3.850" you would also need to remove material from the feed ramp as well. This is why in most of our chassis systems for a Remington 700 long action, we go to 3.715," so it is a drop-in fit. The only exception is our ACC since most customers will use clone actions on that.

Thank you, and will do I was nervous about Taking over 1/8 out of the chassis.

 

[2aBaC̶a̶]

Wait, a standard 300 PRC round wont fit in a standard LA AICS mag?

I just ordered a 300PRC barrel, if i have to get special mags and have limited stock/chassis options im out.

 

[MOUNTIC]

Wait, a standard 300 PRC round wont fit in a standard LA AICS mag?

I just ordered a 300PRC barrel, if i have to get special mags and have limited stock/chassis options im out.

Not with the Hornady Factory ammo. You can seat them deaper reducing the COAL to make it work. Otherwise CIP mags are what you want/need.

 

[gnochi]

Wait, a standard 300 PRC round wont fit in a standard LA AICS mag?

I just ordered a 300PRC barrel, if i have to get special mags and have limited stock/chassis options im out.

You would want the longer mags. Stock/chassis options really aren’t bad; if it’s a stock with BDL inlet use Wyatt’s and M5 there are a few outfits that do CIP AICS bottom metal.

It also depends very much on which action you have. If it’s standard R700, as noted above, you’ll need to adjust the feed ramp.

 

[2aBaC̶a̶]

Nucleus LA, I was thinking if dropping it in a Bravo and be done but this is discouraging.

 

[gnochi]

Nucleus LA, I was thinking if dropping it in a Bravo and be done but this is discouraging.

The Bravo takes CIP length by default - you need a spacer for standard AICS LA mags - and the Nucleus fits a COAL of 3.78 (slightly longer than the COAL of 3.76 that fits in a typical CIP length magazine.)

(Note that the Nucleus “mag length” on the ARC website is oddly worded.)

In your case it’s *more* work to make the not-CIP work.

 

[JohnK454]

According to KRG's website, the Bravo, Xray, and W3 for the M700 will all take CIP mags.

 

[Bandit31]

According to KRG's website, the Bravo, Xray, and W3 for the M700 will all take CIP mags.

They do and should now come with the spacer for non CIP length mags.

 

[2aBaC̶a̶]

Good to hear. Had me worried for a sec. Never really looked into the whole cip mag length thing befor deciding on the 300prc.

 

[2aBaC̶a̶]

So who makes decent CIP mags?

 

[gnochi]

Unless you like futzing with mag lips (which I figure you don’t) you’ll want 3.850 300WM AICS magazines. Personally I like MDT, but I’ve linked the ones I know of:

MDT

Accurate Mag

 

[MDT_OFFICIAL]

So who makes decent CIP mags?

We would be happy to take care of you!

 

[Lindley Machine]

 

[Lindley Machine]

Milled out magwell and the feed ramp, hope to test her on paper soon