Gentlemen: Is there room enough in the magazine to convert an Interarms Mark X 458Win to Lott? Seems like there should be as they offered this in 375H&H. Thanks.

Yes. - Dan

action is fine, box is short. Can be opened, might find another bottom metal.

jeffe

Jeffe- what has to be done to open up the magazine? Is it not long enough or does it have some kind of block inside that is easily removed?

Unless the rifle was originally in 375, the magazine will be too short, as will the receiver opening. If it wasn't a magnum to begin with, the bolt face will be too small, and the receiver feed lips will have to be modified for proper feeding. There is no block (like the old Model 70's) that you can just take out. Files and/or milling machines. - Dan

exactly what dan said

jeffe

It's been 13 or so years since I replaced the bottom metal on my Mark X but at that time the stockmaker told me that he had difficulty finding aftermarket metal that fit the way the 375 Whitworths were opened up. I don't know if this is actually true or a ruse to cover slow delivery. Either way I ended up with the front of the box cut away and left that way. It has functioned perfectly well, too.

Actually, if memory serves, the D size Mk X receivers (375 size) cane from the factory with the extra space taken from the front. Whitworths, it would depend on when it was built. They got their receivers from different sources at different times. - Dan

I just converted a 375 to Lott. There's plenty of room in the box, but the loaded shell will not eject unless shortened less than MAX OAL because of the length of the receiver opening.

Jd,
that's interesting... I thought 375 and 458lott had the same OAL... oh well, there I go, thinking

jeffe

What about the 300 Win Mag? Does it just need rail work and the bolt face opened up? I'm thinking about using one of my JC Higgin's FN actions for a donor.

[ 10-30-2003, 05:30: Message edited by: JBabcock ]

jeffe: They are the same length. A 375 Mark X's ejection port is just a bit short. I tried loading some 300 Gr. SGK's in the 375; they had to be shortened several thousands to eject when loaded.

Dan: My Whitworth is, I beleive, a Mk X and what you say was the same as reported to me. Most bottom metal at that time was designed for actions opened up in the rear and mine was opened in the front. I recall reading years later that some smiths were concerned about metal removal behind the lower lug recess and didn't recommend them for really big calibers. Mine has worked well in spite of that concern.