Gunsmithing .260 Rem chambering question...

[Sixfivesavage]

I'm getting ready to take my parts up to Mr. Hammonds and am gonna take him a loaded round to mag length for AI mags. I'm planning on using the 140 class projectiles like the Amax and 142 SMK but don't have either on hand. I do have some 140 Berger hybrids, I know it's not ideal but would it work ok to load a dummy round with them and plan on shooting all three possibly? I'm not sure what to do since I don't have the other bullets, but want to get things rolling.

 

[BLDTYLRY]

PM me your address and I'll send you a 140gr A-max

 

[turbo54]

I'm willing to mail you a 142smk.

But...

You'll find the throating required for each is quite different, if your aim is to maximize case capacity while keeping the ability to fit magazine and also touch the rifling.

 

[Sixfivesavage]

Thank you both for the offers! It's more than I could have hoped really. You guys are awesome. As far as the throating goes, to which would I be better off perusing. I'm assuming the amax since the rifle may see deer once in a while, but the SMK has put a few down for me too. The good thing about the SMK is the 500 piece boxes.

 

[turbo54]

My opinion only...

I'd throat it .010"-.025" longer than you can reach with a magazine compliant 142smk.

The 142smk is a very forgiving bullet that I haven't found requires being "on the lands", and even throughout "crunchtime", has remained fairly steadily available. I've found the consistency from bullet to bullet to be superior to the 140amax, though many people have great success with the amax. The berger has spotty availability and is very long. I wouldn't choose it unless I was going to do something special to the magazines/feedramp to make it accommodate longer cartridges (as in 2.900" or more). Otherwise, you'll be giving up case capacity and be forced to run it slower, giving up some of the goodness of its high BC.

 

[long range newbie]

I'd just mill the bar in the front of an AI mag then no need for "mag length issues" I can run up to like 3in in an AI mag

 

[turbo54]

I'd just mill the bar in the front of an AI mag then no need for "mag length issues" I can run up to like 3in in an AI mag

3"?

Really?

How?

 

[long range newbie]

look it up. If you hold and AI s/a mag and look in the front and you see how its thicker in the front? Well you take out the spring and guide, then you mill out the two holes and then the bar should come out (sometimes takes a little force) and then you weld the holes back up (make sure you have a square piece of aluminum so it doesn't weld to it) Then you have and AI mag that can feed up to 3in.

 

[turbo54]

look it up. If you hold and AI s/a mag and look in the front and you see how its thicker in the front? Well you take out the spring and guide, then you mill out the two holes and then the bar should come out (sometimes takes a little force) and then you weld the holes back up (make sure you have a square piece of aluminum so it doesn't weld to it) Then you have and AI mag that can feed up to 3in.

Gotcha.

Mine only accommodate 2.950" with the front plate removed. I've never heard of anyone achieving 3" with them.

 

[long range newbie]

I was exaggerating a little but I measured it and its 2.8 end to end