Gunsmithing Brass getting scratched when loading from magazine

[sled_mack]

I just put together a 300 Win Mag on a Rem 700 action. The stock is a Stockys VG2 carbon fiber, with the Stockys bottom metal and internal mag.

Putting the rounds in the magazine, requires a lot of effort compared to my AICS mags. I don't have any other internal mags to compare with. But it does seem excessive.

When closing the bolt and extracting a round, the brass gets scratched from the bottom of the action. I don't know if it is from the force from the magazine? Or if the edges on the bottom of the action are sharp? Also, the round "pops" out of the magazine, it doesn't feed smoothly. I think it is from being hung up on the edges making the scratches in the brass, but I'm not quite sure?

I don't really see a good way of reducing the spring tension (it's an M fold, so cutting it off would just make it unstabe). My next thought is some sand paper on the edges of the action making contact with the brass. But I'm concern that doing so could lead to the rounds not being contained properly.

I realize this is not a lot to work with. But I'm open to suggestions. I'll try to answer any questions that would help, too.

Thanks,
Steve

 

[big_matt_duq]

My 7wsm does it too. I polished the front on the mag box and feed ramp some and it helped a little I think. Haven't used it much since and I think it still needs some tweaking if I remember correctly. I'm curious to see what others say.

 

[longshooter]

Ensure that the he top of the mag is not up into the ramp area. Mag might need grinding here.

 

[Supersubes]

Was this a previously functioning complete rifle in another stock/bottom metal, or did you source individual parts for the build? Could be a conflict in those parts(box, spring, follower). Is the first round hard to load, or just the last one? The box should fit nicely into the cutout in the bottom of the action, and the bottom metal should NOT be clamping against the box(box should float up/down between action and bottom metal). You can smooth out the feed lips, but just address the surface finish, and not the geometry.

If you post some pics of the parts, that might help. Some of the more saavy readers can probably spot an error if there is one.

 

[sled_mack]

Thanks for the replies. I just got back from a business trip. I'll try to dig into this more this weekend.

These are all parts sourced for this build. Stock and bottom metal are new, action was used.

Supersubes - every round is hard to load in the magazine, with each added round increasing the spring pressure. Each round is about equally difficult to chamber.

I'll see if I can pinpoint the contact point scratching the brass before I do anything to the feed lips. My thought was to use the polishing wheel on a dremel tool. That should smooth the surface without taking away any material.

 

[Supersubes]

There are more than a few different followers and boxes that have been used over the years by remington. The difficulty inserting rounds points to something other than surface finish.

 

[sled_mack]

I'm almost thinking two problems. Magazine/spring related to loading, and a sharp edge somewhere causing the scratching. Maybe? Either way, I want to have a good understanding of what is going on before I start doing anything to it.

 

[sled_mack]

I finally got around to working on this today.

I still don't know why the spring was so strong. But, a few days ago I took it out, compressed it completely in a vice and left it there. I figured if I wrecked it, it's not an expensive part to replace. Turns out, it made a world of difference. There is still more resistance than any of my external box mags, but it is a reasonable amount of force required now.

The magazine box itself was not free in the stock/action. The rear of it was slightly bound where it sits down into the action (down when the rifle is upside down in a vice). When it was formed, there were two little corners sticking out that were catching in the action. A few passes of a file and that was no longer binding.

At that point I checked the front of the magazine. It was blocking the path to the feed ramp. A little bit of filing and sanding there, and it was a smooth transition.

However, after all of that the brass was still getting badly scratched. I could see the point on the action that was causing the scratches. As the round moves forward, it was scratching where the feed lips open up. That area felt rough to my finger. Because it is difficult to get in there, I used a dremmel with a buff wheel and polished the entire area. Problem solved!

The next time I order parts I'll probably order another mag spring. There is definitely something odd with this one. But for now, it is feeding smooth and not scratching the brass.

Thanks for all your help.