Suggestions for a short barrel long ranger

[o2bwest]

Just built a 7mm-300 Win Mag with a 22" barrel plus brake. 1 in 8.5 twist. It is sending 180 Bergers at 3025 fps with 76 gr of H-1000. It is a pleasure to shoot and a hammer at 1000 yards. The 180 arrives in 1.25 seconds at 1000 yards at 1896 fps and 1437 ft lbs of energy.

Jeff

On that note, why not a 300wm or 300 wsm? Seems like the short column of the wsm would burn more efficiently in a shorter barrel????

 

[Broz]

On that note, why not a 300wm or 300 wsm? Seems like the short column of the wsm would burn more efficiently in a shorter barrel????

I guess my personal preferences. I have never seen a 300 WSM out run a 300 win mag. We just wanted to see how the 7-300 ran in a short barrel for a pack rifle with some decent long range capabilities. I thought it did pretty darn good. My chrono is accurate and drops were spot on to 1000 and that's as far as I documented them.

Jeff

 

[liltank]

155 Hybrid at 2800'sec is a breeze in a short barrel 308. At 2500' elevation, 59 degrees you have just over 1000 foot pounds at 700 yards.

The 708 looks good too but you're going to be looking at 2600' sec at best with the 162 in a 20-22" tube and at 700 yards the numbers are nearly identical. Less recoil, better barrel life in the 308.

Larger bores are much more efficient with shorter barrels than smaller bores. Bump the 308 to the 168 Hybrid at 2750'sec (easy in a 20-22" bbl), the energy goes up and beyond the 162. In all three cases, the 162 has the best windage but only by a few inches at 700 yards. Bump to the 185 Hybrid at 2600'sec and the numbers are flat ridiculous for a short barrel sub magnum.

If you said, 26" barrel I'd say take your pick. 260, 708, 6.5-284, 308 etc...If you're looking for 20-22", I'd say 308.

M

How are you getting 2750 with 168's? I'm hard pressed to get 2570 out of my 18" 308. Granted the deer can't tell, but still curious as to what load and powder are you using.

 

[Michael Eichele]

How are you getting 2750 with 168's? I'm hard pressed to get 2570 out of my 18" 308. Granted the deer can't tell, but still curious as to what load and powder are you using.

N540 will do the trick.

 

[liltank]

N540 will do the trick.

Ahh, double base powder.

 

[Michael Eichele]

Ahh, double base powder.

I've had a lot of luck with N540 in 308s. Both in accuracy, consistency and velocity. I've found temp sensitivity but it's pretty reasonable. .6'sec per degree which is better than several of other popular 308 powders.

 

[NZ Longranger]

That doesn't sound very apples with apples comparison wise Michael. You're comparing some pretty hot 308 velocities with some pretty weak velocities for the others.
Agreed Jeff, we have proved even with a lot of very short barreled rifle experimentation that the 300WSM can never outrun the 300Win Mag. It simply comes down to capacity. The 300Win Mag has more capacity than the 300WSM, and all else being equal, will always beat it velocity wise. As you shorten the barrel the difference between them lessens, but never to the point the WSM overtakes the Win Mag.
And just to qualify this, we build a lot of very short 16" and 18" barreled suppressed brush rifles as well as the big guns, and have done a lot of experimentation measuring pressure verses velocity so we have true comparisons. Initially we thought the 308 would beat the smaller diameter 308 capacity cases in BC verses velocity, but that proved not to be the case. The 162gn A-Maxes combination of BC verses achievable velocities proved to be the one to beat.

Here's a pic of my wife shooting a trophy Chamois buck at 400 odd yards with a 16" barreled 284 built around a Tikka T3 action with a carbon fibre stock and a 3.5-10 Leupy CDS with custom dial. The overall rifle length here including the suppressor is less than that of a 20" barreled rifle, and weighs just over 6 pounds all up. It pushes the 162gn at 2800fps for 62,000psi out of this barrel length, but the best accuracy proved to be at 2750fps for just under 60,000psi.







Now not everyone wants a rifle that short and light, but we have proved you can still achieve pretty good performance in a surprisingly compact package.

But getting back to the OPs original request of out to 1000 yards I think he said, I wouldn't personally consider any 308 capacity case, or even this 284 load a recommended big game suggestion for that range. There are better tools for that job, even in a shorter barrel. IMHO of course!

 

[Unofficial Gun Addict (UGA)]

But getting back to the OPs original request of out to 1000 yards I think he said, I wouldn't personally consider any 308 capacity case, or even this 284 load a recommended big game suggestion for that range. There are better tools for that job, even in a shorter barrel. IMHO of course!

I'm thinking he said 1000fps @ 700 yards.... And the 308 with the proper bullet/powder combo certainly fits the bill on a 20" barrel with ease,.... and practice.

 

[NZ Longranger]

Fair enough, I should have gone back and rechecked exactly what he said. Personally though, I still think there is better than any of the 308 capacity cases in a short barrel for anything over 500 yards in the fickle mountain winds. Not saying they won't do it if you get it all right, just there are better.

 

[Unofficial Gun Addict (UGA)]

I hear ya... But dang those Berger 215s with a .696 BC is sweet.... Lot of wholop for a short action at distance... And the wind bucking potential is silly good. One thing about rifles though.. There are so many good options!

 

[o2bwest]

I'm thinking he said 1000fps @ 700 yards.... And the 308 with the proper bullet/powder combo certainly fits the bill on a 20" barrel with ease,.... and practice.

To clarify, I said I wanted to maintain at least 1000lbs of energy at 700yds.

 

[MontanaMarine]

Lots of ways to get there. I weigh bullet mass and BC over muzzle velocity.

I shoot a couple 308s with 20 and 22" barrels. Launching the 208 Amax at 2550 and 2600 fps respectively.

At 700 yards, the shorter barrel delivers about 1790 fps and 1480 ft-lbs. Full value 10 mph drift is 28".

I did install Wyatt's mag boxes to extend magazine length to 2.99".

 

[Unofficial Gun Addict (UGA)]

To clarify, I said I wanted to maintain at least 1000lbs of energy at 700yds.

Yeap.... It's been a while since I read the first thread m1000 ft/lbs... 308 maintains that at the ranges I specified earlier with the 215.

 

[WildRose]

Thats interesting. I have a 300wsm and a 7wsm and they are both great shooters. I wonder which one does better out of the short barrel? My hunch is that the 300 will have the higher muzzle velocity even over the 6.5 wsm out of a short barrel. Would that be correct? Bigger bore = more powder burned in a shorter barrel???

Use a faster burning powder than you would with a longer barreled version of the same caliber and problem solved.

Set your velocity target to 2850 with the 140's and you can have the best of all worlds with the 260 AI or 6.5wsm.