7-08 barrel chop

jordang

Well-Known Member
I'm thinking of (well have pretty much made my mind up) having my 7-08 chopped to 16.5" and screwcut for a mod. The masterplan is to shoot 120TTSX @ 3000fps, which I'm assured is perfectly possible.


Just need a sanity check before I take the plunge!!!


Any thoughts?
 
3,000 fps is normal MV for 120-gr out of a 24-inch barrel.
I have two 20-inch 7mm-08s, and they both get about 2,850 or better, depending on loads.

A top end load like 44.0 gr of RL-15 might get over 2900 fps in a tight 20-inch barrel, but not 16.5.
Do you need more than 2800 fps? Do you want some room to give up MV for accuracy tuning? If so, leave the barrel at least 20 inches.
 
I've spoken at length with somebody running the configuration I'm thinking about, although, to be honest you're right, 2800 would be ample. I might bottle it and settle on 18" though when it comes to the crunch!!
 
Hi jordang,
whats the worst that could happen ? New barrel needed ? People told me 18" was too short for a 6.5/47 but now I know its not !!!! Lol
regards
Jimmy
 
Read an article in a NZ magazine a few years back where they looked at the performance of the 308 and 7-08 at 16".
With a 308 they achieved 3000fps using 130gr ttsx / H335 or the 7-08 achieving 3000fps with 120gr ttsx / H335.
edi
 
I would shoot the rifle with a powder, bullet and primer, and measure the velocity and groups BEFORE cutting it off.
It if is not getting 3,000 fps and sub MOA in a long barrel, don't expect to get it in a shorter one.
Not that you need 3,000 fps, but you literally have more room to play with different powders in a 24 inch barrel than you have in 16.
 
Hi there

My 7mm08 is 18". I shoot mainly 140grn bullets and get 2690fps. Does the job admirably on all UK species and is a great length in woodland but still great on the hill. Can't see the point of long barrels for sporting rifles especially for all practical purposes they offer no benefit at normal stalking ranges.

FN
 
I think your 120g 3000fps 16.5" master plan is destined to fail , however I think you will still have a very handy deer legal rifle ..........
 
Problem is I'm shooting 139 grs at min and I'd like to stick with them so I'm wondering what they will do in a shorter barrel ...
 
Using Hornady Superformance 139g SST factory ammo out of a 19 inch barrel, my average from 15 measured shots was 2760 fps
 
Go for it.....NZ gunsmith Scott Traill uses a 10 inch 308 to good effect, google Scott Traill short barreled 308, plenty of info out there......
 
Problem is I'm shooting 139 grs at min and I'd like to stick with them so I'm wondering what they will do in a shorter barrel ...

Hi there

I'm shooting 140's and getting good speed (2690fps) and it's certainly no where near the top end of loading safety so I suspect if you need, that could be bettered and accuracy is outstanding (see picture three at 100m). I regularly shoot as WMS and have little problem getting well placed rounds out beyond 600m. It's about then the loss of velocity shows. I can live with that for all the benefits that a shorter barrel offers.

Three shot group.JPG

Hope that helps with your dilemma

FN
 
Hi there

I'm shooting 140's and getting good speed (2690fps) and it's certainly no where near the top end of loading safety so I suspect if you need, that could be bettered and accuracy is outstanding (see picture three at 100m). I regularly shoot as WMS and have little problem getting well placed rounds out beyond 600m. It's about then the loss of velocity shows. I can live with that for all the benefits that a shorter barrel offers.

View attachment 39737

Hope that helps with your dilemma

FN
Hi fn
thanks for the info that's a great group :) think I will take the plunge as mines used purely as a stalking rifle so the advantages far outweigh any disadvantages
atb Jim
 
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