Browning A-Bolt 7 mag load info

sdupontjr

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Oct 8, 2019
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I decided to start playing around again with my Abolt II medallion 7mag with Boss system. I picked up some 162 ELD-M and H-1000. I have 100 or so R-P brass and just waiting on my primers to come in. Started taking measurements on mag length, COAL, CBTO, etc.

162 ELD-M
3.425" COAL
2.727" CBTO

The browning mag has a max COAL length of 3.390", but can be modified. I ran across another forum where a guy was loading for his original abolt in 300 wm and the newer berger bullets wouldn't fit the mag, however when single fed, drove tacks. So he did this simple modification with a chainsaw file.

This is a pic of my mag with a factory 162 ELD-X Hornady Precision Hunter with a COAL of 3.283"


This is a pick of the modified mag for his 300 wm using 215 berger. Has put about 150 rounds through it with out a problem.


He didn't have a pic of the 215 berger but here is one with 160 AB. You get the idea though.


So, I decided to do a max measurement of my mag.
3.714" from the base to the end of the plastic. Basically file out all the plastic and leave just the metal housing. The plastic could be completely removed but it you notice, they have side ramps that hit the shoulder to keep the round in place. This prevents the round from sliding forward and damaging the tips.

3.714" Max mag length.
3.425" is the max COAL for the 162 ELD-M which would leave me about 1/4" of plastic still to play with.

Question 1, Do these 162 match rounds like jam, .010", .020", lots of jump?
Question 2, In my head, this "should" work. My plan was to start at .010" since my mag allows me to, work up to pressure to try and get max velocity, then use my Boss, which is basically a barrel tuner to tighten my groups. In doing this, I should achieve good velocities as well as groups.

Is my line of thinking correct?

I was going to do this with my Tikka t3 7 mag, but magazine restriction kinda killed that and they both have the same barrel length twist rate of 9-1/2. The Abolt is 24" barrel with additional 3" of boss. So this was a no brainer for me.
 
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Ddubs20

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Jan 17, 2023
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When I messed around with a 162 eldx the COL was around 3.295". Maybe once you settle on powder charge, shoot 2 shot tests of different seating depths around .005" apart.
 
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sdupontjr

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Oct 8, 2019
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I did find some primers finally and they should be here Wednesday. I considered my abolt when I ran across that older thread with the modified mags. Haven't shot it in about 3 years since picking up my T3 308. But after messing around with it, hell my abolt is as slick or slicker than both my tikkas. And I'm not limited to mag lengths incase these 162's shoot like poo. But well see.
When I messed around with a 162 eldx the COL was around 3.295". Maybe once you settle on powder charge, shoot 2 shot tests of different seating depths around .005" apart.
That was the plan. I was going to start at .010" off, then .015" and .020" in the Browning. Can't with Tikka due to mag length.
My COAL with 162 eldx is 3.312" in a Tikka 7 rm. It barely fits in the mag but shoots lights out.
I have read a lot of threads that claim seat to mag length then go from there. I just wish someone would make a longer mag but still flush looking. AICS sticks out so dang far. HCA is coming out with a new billet style mag for Aug 2023 timeframe, but is still limited to 3.410". Only downside is it's not for belted magnums. If some company could get one to 3.500" and still look somewhat flush and stock, then I'd be all over it.
 

SloppyJ

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Feb 24, 2023
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Have you actually shot it that far out? The gun might not even like it that close to the lands and then you've wasted your time. When I first started I was putting everything super close to the lands. Since then, I've figured out that it doesn't seem to be the magic that it's made out to be. Some of my guns like it much further away than that. However, my 280AI likes to be 10-20thou away and I got lucky that I can accommodate 160gr accubonds in the stock magazine at that length.
 

5MilesBack

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I have an older A-bolt 7mag that I shot 175gr Partitions out of for years. A few years ago I tried the 168gr Berger Classic Hunters with H1000 and finished at 3.322" COAL with 69.5gr for the best accuracy.
 
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sdupontjr

WKR
Joined
Oct 8, 2019
Messages
493
Have you actually shot it that far out? The gun might not even like it that close to the lands and then you've wasted your time. When I first started I was putting everything super close to the lands. Since then, I've figured out that it doesn't seem to be the magic that it's made out to be. Some of my guns like it much further away than that. However, my 280AI likes to be 10-20thou away and I got lucky that I can accommodate 160gr accubonds in the stock magazine at that length.
I haven't, was waiting on primers and they "should" be in this week, but well see. But given the Browning has the boss, I can tune with that as well.
 
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