12" HMR barrel

Kernow_Stalker

Well-Known Member
Taking my HMR to the gunsmith tomorrow after work.
Getting the barrel cut to 12" to make it nice and compact for 4x4 shooting. From the calculations I've run the trajectory and power etc doesn't massively alter and it's still pretty damn flat out till past 130 yards!

Anyone else had such a short barrel?

Cheers

KS
 
You'll notice more unburnt propellant in the barrel than usual as you've reduced the effective burn time - on the bright side you'll have a shorter distance to push the squibs out! :D
 
I have a factory 14" barrel on my 1517 runs fine you do get unburnt powder in teh mod but no idea if it happens on longer barrels as have never had one

will get round to running it over a chrono one day
 
A lot would depend on the internals of the moddy. Not much powder or pressure though so I'd say it MAY be a worry on cheaper mods with aluminium internals but even then I'd be pretty surprised.

Hopefully soneone who isn't speculating will comment as I don't, and likely won't, own a HMR.
 
Oh I know I'd love it, I need zero convincing that it's a good tool like :) if I needed longer range vermin than 22lr I'd be tempted by HMR but would likely end up with a small centrefire like a 17 fireball or Rem but realistically I don't need to shoot over 60 yards.
 
Do you find it eats your mod quicker or not?

Edgar brothers who sell the Scirocco mod do a different version for the sub 16" barrels that have the first few baffles made from steel rather than aluminium as the baffles do suffer a bit with gas cutting. I doubt it would make a huge difference though. My barrel started at 20" and was later cut down to 15" and hasn't made any noticible difference to performance other than its much better handling now. The scirocco mod has quite some erosion to the first two baffles which are aluminium and that's after a thousand or so rounds, still got plenty of life left in it though. Although I mainly now use a SAK mod as it's shorter and sounds pretty much the same.
 
Bruce Potts has tested the effect of shortening a 22" Sako Quad .17HMR barrel down to 16" in his excellent book Sporting Rifles. Results shown below, along with the same for .22LR (5 shot groups at each barrel length).

IMG_NEW.jpg

This suggests that down to 16" there isn't a significant change in velocity (Bruce didn't go down to 12"). Has anyone else has got data for .17HMR over a chrono, regardless of barrel length? Bruce's figures don't go down in a smooth curve, and one reason for this could be that .17HMR velocity is very inconsistent from bullet to bullet, especially when compared with his data for .22LR.

Anyone got any figures that might clarify this?
 
You'll notice more unburnt propellant in the barrel than usual as you've reduced the effective burn time - on the bright side you'll have a shorter distance to push the squibs out! :D
Lmfao! :rofl: (I've been a victim!)

ATB Lee
 
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