Opening feed rails std. M700 action to magnum

[tobnpr]

Need to open the feed rails on a std. short action to feed .300 WSM in a BDL.
I've already milled/fitted it with a Wyatts extended box mag, it was originally to be a .260 (new PTG magnum bolt).
Anything beyond evenly removing material from each side until the case clears?

 

[butchlambert]

Need to open the feed rails on a std. short action to feed .300 WSM in a BDL.
I've already milled/fitted it with a Wyatts extended box mag, it was originally to be a .260 (new PTG magnum bolt).
Anything beyond evenly removing material from each side until the case clears?

I like all the great answers that have been posted.

 

[Will Henry]

Opening the rails is likely to be necessary but, just as important is to widen the mag box and machine the cut out in the action to accept it. The last one I did, I opened the mag well by ,050" and widened the box by the same amount. I widen the box by splitting it then filling in the gap. Also modified the follower to center it up in the wider box. Then it is just a matter of opening the rails so the case comes up as you want. It is important that the cartridge doesn't jump out too soon. I hate the WSM's and hate working with them. Just sayin'! I have done the same sort of thing to correct feeding issue on Ultra mags but didn't widen the box as much (about .035") WH

 

[DaveTooley]

From my experience it's not just about the distance between rails. The angle on the bottom side is very important in keeping the case tucked in under the rails.

 

[tobnpr]

Thanks for the info.

Fun, fun...
This is one I'm building for my son, so I griped a bit about the last minute change (including the now "extra" 6.5 blank) but I'll deal with it.

I haven't measured yet, but I'm wondering if this would better be done with "hand" work instead of the mill. Much easier to remove a little at a time checking as I go, and there's not much to the rails- seems a file would make short work of it.

Ordering a Hawkins WSM follower rather than trying to mess with the SA standard one.

Good thing is, shot like a laser- now I just need to get it to feed

 

[DaveTooley]

Personally I'd go straight to a single stack mag box.

 

[nksmfamjp]

Personally I'd go straight to a single stack mag box.

You beat me to it...short fat is cool, but feeding is often a challenge. I’d hate to be a gunsmith working on a staggerfeed.

Who makes a center feed box for a BDL?

 

[Edd]

Who makes a center feed box for a BDL?

Wyatt has them.

 

[tobnpr]

^^^
Looks like I should change out the MBE-05 box I fitted with the .260 in mind- for the center feed CFE-05 for the WSM? Same dimensions, it'll drop in.

I'll call Wyatt's to see how best to modify the feed rails.

 

[Danny1788]

Installing the CFE 9 Magazine Box - Wyatt's Outdoor

 

[Edd]

I think you will only have two concerns when using a CFE-5 and neither one of them will amount to much.

The space between the rails needs to be wide enough for the WSM case to pass thru and you need to make sure your magazine feed lips don't contact the receiver.

 

[tobnpr]

Thanks,
Just ordered from Red Hawk.

 

[Tucker65]

With a center feed box can you load the magazine from the top or do you need to open the floor plate and load from the bottom. I'm thinking you wouldn't be able to slide them in the center feed box like you would do in a detachable magazine.

John

 

[tobnpr]

^^^
Good point.
Dunno- probably will depend on how far the feed lips extend from the rear of the magazine, and whether there's space to get the loaded rounds ahead of them, and slide back under the feed lips (?).

Uncharted waters for me...

 

[DaveTooley]

Stick one in the pipe, turn over pop floorplate and drop two in, close floorplate. GTG

 

[Alex Wheeler]

Yep, if Wyatts make a center feed thats the way to go. Properly tuned you cant even feel the round being stripped from the mag.

 

[tobnpr]

So..minor problem with the center feed mag.
The MBE fit snug as a bug- press fit, wouldn't rattle loose.
The CFE, while supposedly the same size- isn't. It's five or six thou shorter.
Drops in, no play- but not a press fit. The back of the mag is welded closed, while the MBE is left open.
That "spring" tension with the MBE also helps hold it in place.

I had a few ideas, so what's best?
Take a dremel cutoff, and slice open the back of the mag down the middle, like the MBE (why does Wyatt weld the center feed, and not the staggered)?

Do something cheesy, like painters tape at the top of the mag to get a press fit?
A few drops of crazy glue on the bottom of the receiver feed rail (for real...)?

With the base of the case being .555 or so, how much should I open the rails up for clearance (.542 now).
I don't see any reason to be conservative here since the case is guided by the mag feed lips- ten thou a side -.575 total- sound about right?

 

[DaveTooley]

Center feed is welded to maintain the distance between the feed lips. DO NOT CUT IT.
Why can't the mag float a little? If it really bothers you bed it into the action. But only after final assembly and function testing so you know everything works properly.

 

[tobnpr]

^^^
Thanks, just my OCD at work.
I hadn't checked it with the stock/bottom metal fitment, had a concern it'd be rattling around in there if there were clearance to the bottom metal. Turns out, nearly perfectly flush- no movement possible.

 

[tobnpr]

Dave,
Won't feed worth a damn... rounds are stovepiping.

Rounds are SAAMI spec OAL. Lots of boolit stuffed in the case (180's) .
Mentioned previously this action was supposed to be a .260 which is why I installed the extended mag. Now it appears to me that this extra length may be causing the problem.

The feed lips on the mag are relatively short (seems to me, anyway). If the round is toward the front of the mag (with the free space at the rear), the feed lips don't extend far enough forward to prevent the rounds from orienting nose- up. I thought less force from the follower might help, so I ground off the corners of the follower spring (per Wyatt) but it had no real effect. The rounds are popping up past the feed lips before being fully stripped past by the bolt.

Single round does feed and eject properly- so perhaps it's a combination of the orientation of the round combined with the follower tension.

Any suggestions (sorry 'bout the fuzzy picture)? Maybe adjust the feed lips for more tension to keep the rounds from popping through until they're past them?