vertical strings with Wyatts magazines

[jamiedvr]

I have built 2 Rem.700s. One in 375 RUM. the other in 416 Rigby. I had put a Seekins detachable magazine on both and they wouldn't feed very well so I sent them to Wyatts to have Kevin put one of his magazines in them. When they came back they fed great but they both shoot vertical strings. I talked to Kevin and the smith that had built the guns and they are both stumped. With out the magazines in the guns they both shoot 3/4" groups, with the magazines in they shoot vertical 2 1/2" to 5 1/2". It has something to do with the magazines.

Does anyone have any experience with this problem?

 

[Coyboy]

are they external box magazines or the internal box with BDL floorplate?

 

[jamiedvr]

Five round external.

I opened up the receiver front, back and both sides. trying to get it so the magazine doesn't touch the receiver at all. I have gotten quite an improvement with the first group, 2" but still not what the gun can do.

 

[Coyboy]

try shooting groups by single feeding.

WITH the magazine in place.
BUT with NO cartriges in the magazine.

if that groups well.

Then the culprit may-be the pressure pushing up on the bolt from the remaining cartriges in the magazine, and not the magazine itself.

 

[LongBomber]

Have you looked at the tip of the bullets in the mag after you fire a round? I only ask as my 338edge improved will break the plastic tip off an accubond or a ttsx, and will bend the tip of a SMK or partition. I have to single feed my rifle. It may not be a mag touching issue, but a badly deformed bullet problem.

Just throwing it out there.

 

[jamiedvr]

COYBOY

It is 95 degrees and 70% humidity here today so hard to get good data. If you leave the guns out the barrels don't cool. If you take them in they get cool but when you take them out they condense. This being said the first shot out of both guns I take with a grain of salt.

I shot a four shot group with the 416 Rigby one at a time with none in the magazine three shots in .544" with the first shot opening it to 1.084". If I take the last two shots of the previous group it would be a 5 shot group of just over 1/2"

I shot a three shot group with the 375 RUM with the magazine full but not taking one out, I would put a new one in each shot. The group measured 1.5" but the last two were touching. Due to the condensation I didn't think the first shot was representative so I loaded two more. The last four were then touching .712".

I also shot two solids out of each gun they were right at .75 for each gun.

I know that this could have been done better but the barrels heat up very fast, and these guns really kick so I didn't want to shot to much more at one time.

I think you are right about the changing pressure on the bottom of the bolt as the magazine is used up but I don't have a solution.

Thanks for any help, these guns and I need to go to Africa in two weeks. I just need to get them to shoot ok then I can have them worked on when I get back if I need to.

 

[jamiedvr]

Long Bomber

I am using TSX and BBS so the points stay good.