PRI mags for long AR boolits

[garandman]

If yer handloading your 223 rounds and are looking for just a tiny bit more length in the mag body, I recommed Precision Reflex ....

https://www.precisionreflex.com/Detail.aspx?PROD=186787&CAT=4294

 

[TonyTheTiger]

ASC stainless gets you to 2.315" or so as well.

 

[garandman]

ASC stainless gets you to 2.315" or so as well.

Wow. PRI will only get to maybe 2.290.

These fit an AR magwell? Alot less 'spensive too.

 

[garandman]

https://www.ammosc.com/products/mag...ess-steel-15-rd-blocked-20-rd-magazine-detail

 

[TonyTheTiger]

Yup, they work great.

 

[garandman]

Yup, they work great.

Just ordered 3.

 

[Rlb40x]

I made my own cavity back mags.
I drilled a 5/8” hole in the front of a Valkyrie magazine, then cut the edges down to blend into the hole. I can load 6-7 rounds in a mag, but I can load as long as I like.
My 95 grain loads don’t stick out to far.
Take a spare steel mag and give it a try.

 

[garandman]

I made my own cavity back mags.
I drilled a 5/8” hole in the front of a Valkyrie magazine, then cut the edges down to blend into the hole. I can load 6-7 rounds in a mag, but I can load as long as I like.
My 95 grain loads don’t stick out to far.
Take a spare steel mag and give it a try.

Pic? I can't envision what yer describing....

 

[TonyTheTiger]

I made my own cavity back mags.
I drilled a 5/8” hole in the front of a Valkyrie magazine, then cut the edges down to blend into the hole. I can load 6-7 rounds in a mag, but I can load as long as I like.
My 95 grain loads don’t stick out to far.
Take a spare steel mag and give it a try.

I took it a step further because I can't leave well enough alone. Filed out the front of my magwell to get to 2.41".
@garandman pics and details in this thread:

Longest internal length AR mags

What would be the magazine with the longest allowable case length for the AR15 platform? Bought a couple ASC mags that advertise 2.316” of internal length but all I could get in them was 2.270” with a 77gr Berger. Any insight would be helpful. Thanks.

www.snipershide.com

 

[garandman]

I took it a step further because I can't leave well enough alone. Filed out the front of my magwell to get to 2.41".
@garandman pics and details in this thread:

Longest internal length AR mags

What would be the magazine with the longest allowable case length for the AR15 platform? Bought a couple ASC mags that advertise 2.316” of internal length but all I could get in them was 2.270” with a 77gr Berger. Any insight would be helpful. Thanks.

www.snipershide.com

Nice !

I'm running a 1:8 twist, so 2.320" s/b good enuf. We shall see.

 

[TonyTheTiger]

8 twist here too. The longer bullets that won't work at regular mag length really are in a different league than the short stubby 75/77gr.

 

[garandman]

8 twist here too. The longer bullets that won't work at regular mag length really are in a different league than the short stubby 75/77gr.

I'm getting ready to run some 73 ELD's and 69 TMK's.

You get the 75 / 77's to stabilize in your 1:8??

 

[TonyTheTiger]

Absolutely. Never had a problem with them in an 8 twist, even in 14.5" barrels at 2550fps.

 

[Earnhardt]

When you guys are seating the bullets out farther, (closer to the lands) with these modified mags, are you seeing jumps in pressure and primer damage?
Even when the bullet and powder load remain the same?
Thanks

 

[TonyTheTiger]

No, just the opposite. I still can't hit lands so I'm not pressure spiking that way. But I assure you if I kept the same powder charge and bullets but loaded to mag length some wild things would happen.

 

[garandman]

When you guys are seating the bullets out farther, (closer to the lands) with these modified mags, are you seeing jumps in pressure and primer damage?
Even when the bullet and powder load remain the same?
Thanks

I haven't personally tested it (other than not seeing any pressure signs for any length load I've ever tested) but physics theory says a larger case volume (due to shallower bullet seating) should result in LOWER pressure.

Only time I've ever seen pressure signs is when I've loaded out past the published data (in terms of powder charge) .

 

[MontanaMan]

8 twist here too. The longer bullets that won't work at regular mag length really are in a different league than the short stubby 75/77gr.

Tony,

Which significantly better (heavier, longer, higher BC) bullets have you been able to load into the ASC's?

At what kind of velocities?

MM

 

[garandman]

Tony,

Which significantly better (heavier, longer, higher BC) bullets have you been able to load into the ASC's?

At what kind of velocities?

MM

Hornady 73 ELDs will work in their stated internal mag dimension of 2.312" .... at 0.020" off the lands in my 1:8 twist WOA bbl will give an OAL length of 2. 990" .... they have a BC of 0.397.



Some quick testing this a.m. showed some real promise with 24.0 Varget. One-holing @ 100y.... then my gun went down.

 

[MontanaMan]

Varget is an accurate powder in most AR's but it generally comes up short on velocity to numerous other good powders & it's a longer extruded granule, so it doesn't meter through a powder measure really well either.

I only use it if I can't get something else to work as well.

What kind of velocity are you getting?

MM

 

[garandman]

Varget is an accurate powder in most AR's but it generally comes up short on velocity to numerous other good powders & it's a longer extruded granule, so it doesn't meter through a powder measure really well either.

I only use it if I can't get something else to work as well.

What kind of velocity are you getting?

MM

I'm testing 8208XBR also. Haven't been able to velocity test the 73 ELD's, but 73 Bergers were in the 2650 - 80's

 

[MontanaMan]

There's some interesting info in these 3 links...............parts of a multi-part analysis of a bunch of different powders attempting to dupe MK262 performance.

More or less matches the loads & velocities I gotten with the powders on his list that I've used. I've pretty much settled on 8208, AR-Comp, V V-133 (lighter bullets) & 2000-MR.

Varget

8208 & AR-Comp

2000-MR & IMR 4895

MM

 

[TonyTheTiger]

Tony,

Which significantly better (heavier, longer, higher BC) bullets have you been able to load into the ASC's?

At what kind of velocities?

MM

Into the uncut ASC's? I got 75ELD's in there but the case mouth was slightly over the ogive. Didn't matter though as the 75's wouldn't shoot that far from the lands.

But some of the mag friendly heavies benefit from longer loading. The 77 TMK, 73 ELD and 77 RDF are all pretty long and the extra .05" the ASC mags gets helps free up room for powder. They are all pretty jump insensitive so accuracy wasn't noticeably improved. I can't remember what velocities were exactly but I know the extra powder I could fit in was always good for at least 50fps.

Cutting mags is when it gets interesting. 75 ELD's can happen. Then filing magwells gets you into 80 ELD or 85 RDF territory. I'll be testing both in the future.

 

[Rlb40x]

Pic? I can't envision what yer describing....

 

[Rlb40x]

I could have done a little better job with a different tool for cutting the sides down, lesson learned.