300 PRC conversion to 300 WSM - Mag Box

[JPatzig]

I built a 300 PRC rifle and am now re-barreling to 300 WSM. Currently built as below, and I'm trying to figure out which mag box and follower I need for reliable feeding in a Defiance long action. Alot of mixed messages out there for what works and what doesn't. Appreciate the help!

Current parts:
DEFIANCE ANTI LONG ACTION MAG BOLT FACE
Hawkins M5 Oberndorf Bottom Metal Aluminum
300 PRC Wyatt box + follower
AG Composites Privateer

 

[martinakl]

I built a 300 PRC rifle and am now re-barreling to 300 WSM. Currently built as below, and I'm trying to figure out which mag box and follower I need for reliable feeding in a Defiance long action. Alot of mixed messages out there for what works and what doesn't. Appreciate the help!

Current parts:
DEFIANCE ANTI LONG ACTION MAG BOLT FACE
Hawkins M5 Oberndorf Bottom Metal Aluminum
300 PRC Wyatt box + follower
AG Composites Privateer

Try what you have right now. Gunsmith can probably tweak feed lips to get it to work (if it doesn't already).

Otherwise, you may have to switch the a Hawkins M5 DBM system. So, new bottom metal and a compatible detachable box magazines. Different manufactures magazines have slightly different specs but probably something built for the Lapau or RUM is the direction I'd look. Some "300 Win" magazines may work as well. Takes some research depending on preferred brand.

As you can see, the Hawkins DBM bottom metal comes is three different long action configurations. That choice will guide your magazine choices...

Hawkins Precision M5 DBM – M5 Detachable Box Magazine

The Hawkins Precision M5 DMB is designed for precision shooters who want a superior experience. Browse our M5 detachable box magazines online today!

hawkinsprecision.com

 

[Rick Richard]

Anything that is a center feed

 

[JPatzig]

Try what you have right now. Gunsmith can probably tweak feed lips to get it to work (if it doesn't already).

Otherwise, you may have to switch the a Hawkins M5 DBM system. So, new bottom metal and a compatible detachable box magazines. Different manufactures magazines have slightly different specs but probably something built for the Lapau or RUM is the direction I'd look. Some "300 Win" magazines may work as well. Takes some research depending on preferred brand.

As you can see, the Hawkins DBM bottom metal comes is three different long action configurations. That choice will guide your magazine choices...

Hawkins Precision M5 DBM – M5 Detachable Box Magazine

The Hawkins Precision M5 DMB is designed for precision shooters who want a superior experience. Browse our M5 detachable box magazines online today!

hawkinsprecision.com

Ok, I'll try it first. With my current set up, the follower just jams the round up into the lips on the defiance action, which aren't adjustable of course. But it is center feed. Really hope to keep my bottom metal, prefer that over detachable mags for this gun.

Anything that is a center feed

Wonder if I'll be ok on my current set up then.

 

[Rick Richard]

Ok, I'll try it first. With my current set up, the follower just jams the round up into the lips on the defiance action, which aren't adjustable of course. But it is center feed. Really hope to keep my bottom metal, prefer that over detachable mags for this gun.



Wonder if I'll be ok on my current set up then.

Try it first before you make any assumptions that it will not.

 

[tobnpr]

With the BDL cut on the receiver, are the feed rails wide enough for the fat .300 WSM?

 

[JPatzig]

With the BDL cut on the receiver, are the feed rails wide enough for the fat .300 WSM?

Good question. 300 PRC rounds feed fine, and they're .532" at the widest. 300 WSM looks to be .555" at the widest, so slightly bigger.

 

[JPatzig]

With the BDL cut on the receiver, are the feed rails wide enough for the fat .300 WSM?

Got some 300 WSM brass and tried...no the feed rails aren't big enough. At least not big enough to feed rounds into the BDL from the top. So what are my options? Have gunsmith tweak the feed rails? Or go to DBM like Martin said?

 

[tobnpr]

^^^
Thought that would probably be the case.
Opening the receiver up is simple enough (I did it on a std. short action for the WSM) to use DBM bottom metal.
I suspect- but no first hand experience- that the WSM would be tricky to feed in a LA with whatever machining could be done to modify the feed rails. The short, very fat case is an animal unto itself. Perhaps another smith here that's been there, done that can comment.

Going with the DBM would be much more reliable IMO.

 

[JPatzig]

^^^
Thought that would probably be the case.
Opening the receiver up is simple enough (I did it on a std. short action for the WSM) to use DBM bottom metal.
I suspect- but no first hand experience- that the WSM would be tricky to feed in a LA with whatever machining could be done to modify the feed rails. The short, very fat case is an animal unto itself. Perhaps another smith here that's been there, done that can comment.

Going with the DBM would be much more reliable IMO.

Gotcha, thanks for your feedback. So the rails need to be opened up, even for DBM?

 

[tobnpr]

Gotcha, thanks for your feedback. So the rails need to be opened up, even for DBM?

Well, short answer is yes- natch. Whether an internal box or DBM, the case has gotta pass thru the receiver cutout.

If you check their site, the action is available in "BDL" cut, and "AI/AW" cut for DBM's.
You ordered the BDL cut to fit your Hawkins bottom metal.

Factory M700's are available in "standard" LA, and "magnum" LA- and it's not just about the boltface. The magnum LA has wider feed rails/receiver cutout for the likes of the Ultras and WSM's.

I would check with Wyatt's and see what box would be the best option for the WSM. You're definitely going to need a centerfeed box for the WSM, but which one that would be in a long action is the question. With a centerfeed box you're no longer relying on the receiver feed rails- the box has feed lips (which are adjusted) to control the round. I think the CFE-12 would be the correct box- but definitely confirm with Wyatt's first. Opening the feed rails for a centerfeed box is easily done by any smith, you certainly don't need extended length so no other mods like the bolt stop are needed.

Keep us posted on what you find out, curious myself which box would work best for this.

 

[JPatzig]

Well, short answer is yes- natch. Whether an internal box or DBM, the case has gotta pass thru the receiver cutout.

If you check their site, the action is available in "BDL" cut, and "AI/AW" cut for DBM's.
You ordered the BDL cut to fit your Hawkins bottom metal.

Factory M700's are available in "standard" LA, and "magnum" LA- and it's not just about the boltface. The magnum LA has wider feed rails/receiver cutout for the likes of the Ultras and WSM's.

I would check with Wyatt's and see what box would be the best option for the WSM. You're definitely going to need a centerfeed box for the WSM, but which one that would be in a long action is the question. With a centerfeed box you're no longer relying on the receiver feed rails- the box has feed lips (which are adjusted) to control the round. I think the CFE-12 would be the correct box- but definitely confirm with Wyatt's first. Opening the feed rails for a centerfeed box is easily done by any smith, you certainly don't need extended length so no other mods like the bolt stop are needed.

Keep us posted on what you find out, curious myself which box would work best for this.

Thank you, appreciate the help.

 

[North Idaho Hunter]

We've had guys run the hawkins m5 hunter DBM with a 300 PRC magazine combined with hawkins' new spacer kit. This will give you the no fuss drop in fit you're wanting to achieve.