Long action magwell length

[osis32]

Im looking at getting a chassis and I'm seeing different magwell lengths. 3.85" Being the longest and a choke in the 3.7"range. I think I read somewhere the new 300 prc has is using the 3.85"oal but I only shoot 300 win mag. Does the magwell inlet matter for that?

[ShaunBrady]

The magwell inlet always matters. The first problem is everything needs to fit. Magazine to the magwell, magwell to the action. Many factory actions are not long enough or positioned properly to load from the 3.850" magazines. They can generally be opened up to work though.

The case length on the 300wm is longer than the 300prc. Most factory ammo is shorter.

How much magazine length can be used depends on the freebore of the chamber and the bullet you intend to use. With a 230 hybrid loaded so the rear of the bearing surface is at the back of the case neck, the OAL is 3.770". It'll barely fit in the magazine with the 3.850" outer dimension magazines. A 230 ATip set up the same way will not fit.

The 300wm reamer I use puts the 230 Hybrids touching the lands at 3.625". The ATip loads to ~0.085" longer.

The factory chamber R700 5R in 300wm has 215 Hybrids touching the lands at ~3.66". PTG makes cheap bottom metal for R700s that use the intermediate length AICS pattern magazines. That magazine has an outside dimension of 3.775" and will take OALs to ~3.700". That bottom metal fits BDL cutouts after removing a little material between the mag and trigger wells. That gun doesn't have enough twist to use the long 230 grain bullets.

In general, additional magazine well length is cheap performance if the action has a large enough opening and the barrel has enough freebore/twist to use the long/heavy bullets.

If you're shooting 180 grain power points ore 190smks, never mind.

[osis32]

It's a Remington 700 sendero sfii. Im not sure what the factory chamber specs are. Probably the same as the 5r. Im still kinda new to this so I'm not 100% on everything you're talking about. I guess my question is using oversized magazines detrimental in any way if my chamber is shorter but I'm using properly sized bullets

[TheOriginalDan]

IIRC, for a factory Remington you'll want either a 3.715" or 3.775" magwell. The 3.850" CIP length magwell would require modification to the action to feed properly. Personally I would go longer than shorter to give yourself more flexibility down the road

[ShaunBrady]

IIRC, for a factory Remington you'll want either a 3.715" or 3.775" magwell. The 3.850" CIP length magwell would require modification to the action to feed properly. Personally I would go longer than shorter to give yourself more flexibility down the road

This is the short version of my post. Even more concisely, longer is better until it becomes more work than it's worth.

It wasn't clear from the first post what action it was.

With chassis, the magwell choices are usually only 3.715, the original Accuracy International 300wm version, or 3.850, the original Accuracy International 338 Lapua. If the rifle came from Remington as a 300wm, it won't have a large enough opening to use the 3.850 magazines.

If you wind up jumping the bullets in a factory barrel because you're limited by magazine length, it's not the end of the world. With a 10 twist, the 215 hybrid is probably the best bullet to run and it won't have to jump much from the shorter magazine.

[jimmykan]

Im looking at getting a chassis and I'm seeing different magwell lengths. 3.85" Being the longest and a choke in the 3.7"range. I think I read somewhere the new 300 prc has is using the 3.85"oal but I only shoot 300 win mag. Does the magwell inlet matter for that?

The Accuracy International and Accurate-Mag magazines for long action CIP support a maximum cartridge OAL of 3.75" - 3.77".

If the 300 PRC is is using 3.85" OAL, then it is either being single loaded, or using a modified magazine with the front wall of it machined off, with a clearance channel added to the magazine well.

[sigstroker]

Everything I can find for the .300 PRC says 3.7 oal. But I don't see anything that specs what kind of bullet that is.

[osis32]

http://pacifictoolandgauge.com/accurate-mag/1365-sssf-300-win-mag.html

So here is where I'm getting confused. They're all 300 win mag but 3 different lengths. I am looking at the xlr chassis and it is 3.85. Mdt has a range of magwell length similar to the magazine's on this site. Im very ignorant of a lot of these things so I apologize

[kevins750]

pretty sure I have a 3.775 on a rem 700 7 mag with ptg bottom metal.

[mmlook]

http://pacifictoolandgauge.com/accur...0-win-mag.html

So here is where I'm getting confused. They're all 300 win mag but 3 different lengths. I am looking at the xlr chassis and it is 3.85. Mdt has a range of magwell length similar to the magazine's on this site. Im very ignorant of a lot of these things so I apologize

the cartridge for mags should only define the follower and feedlip spacing.

so the common ones for LA's are:
1. 30-06(non Magnum)
2. 300WM(Magnum)
3. 338LM(Lapua Magnum)

now for actual mag length and DBM inlet or chassis inlet
this should cover 90% of what's out there(Hawkings, KWM, Badger)

standard is 3.715"
extended is 3.775"
CIP/CIP+ is 3.850"

[osis32]

Sounds like I want the 3.775. That's what I wanted to know. Thank you gentlemen