Long Action .308WIN ?

[wigwamitus]

I got some berger 155.5 grain ammo, I can shoot it out of my short action .308WIN but have to single load the rounds as they won't fit into the PMAGs. I put a PMAG in the gun and top load one round and it cycles fine.
If I built a long action .308WIN and used my .300WM magazines would I be able to run long COAL ammo with "no" issue ? The rounds seems to fit into the .300WM magazines just fine.
(someone might say, they already did that, its called a .300WM )

 

[jda2631]

Is this factory loaded ammo? Do you have a set of calipers to measure the overall length of the cartridge? Why not just use a different bullet though?

 

[b6graham]

run real AICS mags that allow for 2.96 oal

not sure why your 155s are so long though seems a little odd...

 

[wigwamitus]

Well, ok, you asked

I am going thru decision making process as to whether or not to retire .300WM and go strictly with a pair of .308s.

The process hinges on the results of testing with 4 flavors of 155 I've been assembling ... and yes this is all factory right now.

The external ballistics numbers I've run so far, indicate the 155gr bullets can get into the ball part of the 190gr .300WM round ...

I want to shoot around 200 rds of each of these 4 cartridges during April and redo the analysis using real world numbers. Then we can decide. And logistics is a part of the consideration. And even if one of the 155s looks "good" after the testing, we still have to decide if it is worth reloading that cartridge as the cartridges we are testing are not highly available. So reloading would be required and the time/effort for that needs to be factored in to the decision.
But, keeping a 3rd bolt gun (the .300WM) up and running year after year, takes a certain amount of cost and effort and that gets factored in as does the idea, that in a pinch, the 308s can all shoot each others ammo.

Berger website doesn't show the COAL for the 155.5 FULL BORE cartridge
http://bergerbullets.com/product/308-winchester-155-5gr-fullbore-target/

And I don't have calipers but using a tape measure the COAL of the berger cartrridge is almost exactly 75mm.

==
The next closest bullet competing with the berger bullet is the SMK 155 (#2156) which is shown as the HSM 155 load in the chart.

 

[b6graham]

just get aics mags without the binder plate. accurate and mdt both make good ones

 

[wigwamitus]

Tried a real AI mag (came with the AI) and the cartridge is still too long ... though perhaps it has the "binder plate" in it ? Will hunt around for "binder plate" ... the box says the "approximate COAL is 2.920 inches"

 

[THEIS]

Hi,

Just run a long action in 308 like the M24's.

Sincerely,
Theis

 

[b6graham]

Tried a real AI mag (came with the AI) and the cartridge is still too long ... though perhaps it has the "binder plate" in it ? Will hunt around for "binder plate" ... the box says the "approximate COAL is 2.920 inches"

AI mags have a binder plate

 

[jda2631]

https://accurate-mag.com/shop/magazines/308-winchester-7-62x51mm-dssf-magazine/

as b6graham said, you can get these without the binder plate so they you can use up to 2.950" COAL.

 

[wigwamitus]

Yup, I see binder plate removal process

https://www.snipershide.com/shooting/threads/removing-ai-magazine-spacer-plate.5099/

and mags sold without the binder plate

https://www.anarchyoutdoors.com/mdt-metal-magazine-short-action-w-o-binder-plate/


So THANKS, that seems to solve the problem without a new gun !!!

==

... Just run a long action in 308 like the M24's ...

Right, that's exactly what got me thinking along this line, but if I can solve the problem with different mags, that will be easier and lower cost (though if I decide to give up on the .300WM, I could get a new barrel and bolt and build an LA .308 without having to get a new action)

 

[wigwamitus]

I ordered one of the MDT "no binder" mags ... but per the SH post above, I also need to cut a notch for the rounds farther down in the mag to be able to move up towards the top of the mag after the top round is stripped off by the bolt. Otherwise, the feed ramp blocks.

==
The relevant words that go with the pic are "No need for a mill, I did mine with a drill press, and notched my action with the burly bit on a die grinder. "

And the pics