270 Win to 300 Win mag

[Brandon1]

New member here and I have a question or two.

I'm not new to working on guns and have my own Bridgeport mill and a lathe here at home. So here comes the question.

I have a 110 LA that I bought back about 97 or 98 it had the blind double stack internal magazine.
I got the itch to swap calibers from 270 to 300 win mag. Here's what I have done this far. I bought and headspace the barrel, swapped bolt head, bought a accu stock and accurate mag bottom metal. Stock is on and fits fine as does the bottom metal.
However the magazine likes a good bit before it will lock into place. It looks like I need to mill about .200 off the back of the mag well area on the receiver so that the mag will be in the correct position to lock into place.
Does anyone have any photos of the back end of the receiver of a mag fed 300 win mag so that I can see how much I need to mill off? A blueprint of a newer receiver would be awesome.

[Robinhood]

Yep. Brandon you bought a center feed stock and have a stagger feed action. That is causing the precise issue you describe. Your correct magazine attaches to the action. removing material on the back end will solve your problem. Clamp it good and get after it! I would indicate the bottom of the mag well. Also measure the depth at center line and measure the rifle with the mag installed. You may need to deepen the inlet but I think you are deep enough with the center feed stock. You need a little clearance to make sure the action seats correctly.

[Brandon1]

Got it sorted, I had to remove material at the rear of the mag well area. Test fitted again then had to remove a small amount in the front as well. Mag fits and functions as it should now.

[Dave Hoback]

I know I’m not alone in saying: would love to see some progress pictures. Doing this has come up a couple times and some others have done it. I am not among those, yet I know it can be done. Would certainly be informative to those looking to do this in the future as well, if there are some reference pictures to give some pointers. I myself have actually very successfully duplicated and passed on exceptional working parts systems by recreating the parts from photos & videos alone. They truly can be so very helpful to many others.

[Brandon1]

I'll try to get a few pix posted in a day or so.
Basically I had to mill the bottom of the receiver even with the top portion of the back end of the mag well area. Essentially the portion of the receiver that the blind magazine clipped into had to be milled away using a 1/4 carbide endmill. After test fitting I noticed that the mag was almost in position but was now hitting in the front. So back in the mill it went. On the front of the mag well on the receiver there was a slot milled for the front of the blind mag to set into. I milled to that cut out then test fitted again. It was a perfect fit. Mag was sitting correctly and feeds flawlessly.

I should have taken some pix in process, I cerakoted it on Saturday so now I'll have to point out the milled away portions.

[Brandon1]

https://imgur.com/a/3bzgXua

[Dave Hoback]

Looks good. What color Cerakote is that? I sprayed mine Armor Black & Tactical Grey for the Chassis.

[Brandon1]

It is Moss E-210

[Dave Hoback]

Ahh, the E-series. I’ve been using the H-series, but I’m getting ready to do another barrel & planning to try the C-series. (Air dry). Interesting that’s it’s air dry, but supposed to be high heat. I want to test the difference in durability. The H is supposed to be higher, but I’m not convinced. Spray on paint technology has come a long way in just the last several, maybe 10 years.