Short-barrel-magnum-chambered rifles?

[BilboBaggins]

I'm pretty new to long range shooting/hunting and I'm a little confused on the effects of short barrels on magnum calibers. For context I am considering building a tikka 7 PRC that I will run suppressed, looking at a 20 inch barrel.

Obviously chopping the barrel will reduce muzzle velocity. I'm not worried about this as I'd only take a shot at an animal out to 500 yards, absolute max. But how does chopping the barrel affect accuracy? I have seen some say that the incomplete powder burn causes muzzle velocity variation between shots and therefore a reduction in accuracy at longer ranges. Is this true? If so is can it be negated by hand loading? I would only be using factory ammo in the short term, but I'd like to start hand loading at some point.

Are there any other deleterious effects on accuracy or what have you by using a short barrel?

 

[Q_Sertorius]

With the right modern powders, you should still get consistent burn from a 20” barrel.

PS - if you are setting your maximum range at 500 yards, the 7 PRC is “more gun than you need.” You can get effective terminal performance with much less powder burn and recoil.

 

[BilboBaggins]

With the right modern powders, you should still get consistent burn from a 20” barrel.

Ok so consistent as in the same amount of powder remains unburnt each shot? Is this the case with most factory ammo?

 

[Q_Sertorius]

Ok so consistent as in the same amount of powder remains unburnt each shot? Is this the case with most factory ammo?

Consistent as in it will burn all the powder.

 

[BilboBaggins]

Consistent as in it will burn all the powder.

Wow ok that's interesting. Makes me wonder why some people in the "is a X inch barrel too long for a suppressor" threads argue so adamantly for 24 or even 26 inch barrels... I'd much rather have a handy rifle than musket if accuracy is equal!

 

[KenLee]

Inside 500, I'd go with a 20 inch barreled 300wsm...and not a Tikka.

 

[BilboBaggins]

Inside 500, I'd go with a 20 inch barreled 300wsm...and not a Tikka.

I think that would be a little too much recoil for me. Tikka seems like a good cost effective option but I am open to arguments otherwise.

 

[Q_Sertorius]

I think that would be a little too much recoil for me. Tikka seems like a good cost effective option but I am open to arguments otherwise.

There are no good arguments against a Tikka. Unless you prefer the Sauer 100. For bargain rifles, it’s hard to do better.

Inside of 500 yards, and at sea level, a 20” 6.5 PRC or .270 Winchester will keep a decent bullet above 1800 FPS. At higher elevations, you can use even smaller cartridges and remain effective.

This is my 21” .270 shooting factory Hornady Whitetail 130-grain bullets at sea level (starting at actual verified muzzle velocity, not on the box values).

That rifle puts 10 shots into a 3.5” group at 300 yards using factory ammo. I haven’t had the chance to test it at further ranges.

 

[Q_Sertorius]

Wow ok that's interesting. Makes me wonder why some people in the "is a X inch barrel too long for a suppressor" threads argue so adamantly for 24 or even 26 inch barrels... I'd much rather have a handy rifle than musket if accuracy is equal!

Even if the shorter barrel burns all the powder, you still can get more muzzle velocity from longer barrels.

Edit - and my normal rule is that I don’t want my overall barrel + suppressor length to exceed 26”. I have one rifle, a .25-06, which breaks this rule by having a 24” barrel and a 4” suppressor (an OG 6.5).

 

[KenLee]

I think that would be a little too much recoil for me. Tikka seems like a good cost effective option but I am open to arguments otherwise.

I'd bet felt recoil of an x-bolt 300wsm is no more than a Tikka 7prc. Tikkas kick hard for caliber. Tikkas all have long action receivers. Stocks feel awful and most remotely serious shooters replace them. Then there's only one correct location for a safety, top center of the tang.

 

[BilboBaggins]

I'd bet felt recoil of an x-bolt 300wsm is no more than a Tikka 7prc. Tikkas kick hard for caliber. Tikkas all have long action receivers. Stocks feel awful and most remotely serious shooters replace them. Then there's only one correct location for a safety, top center of the tang.

The stocks are subpar but because of that there's tons of aftermarket options. I'm planning to swap the stock. And 7 PRC is long action anyway. You got me on the safety though.

 

[BilboBaggins]

Even if the shorter barrel burns all the powder, you still can get more muzzle velocity from longer barrels.

Edit - and my normal rule is that I don’t want my overall barrel + suppressor length to exceed 26”. I have one rifle, a .25-06, which breaks this rule by having a 24” barrel and a 4” suppressor (an OG 6.5).

Right but if velocity is adequate those people are crazy for toting around such long guns.

The 270/6.5 PRC route is enticing but I want a one and done rifle for medium to big game. I'd like to take shots at 500 with confidence even if it's not a perfect broadside shot. A 20 inch 7 PRC maintains 1500 ft lbs of energy out to 800 yards with 175 gr eld-x. Seems like a no brainer if you can handle the recoil. I deer hunt with a 9lbs 7 rem mag (my dad's rifle) and the recoil doesn't really bother me so I see no reason not to get the 7 PRC.

Planning on a 6 inch suppressor so I'll be right at 26".

 

[Q_Sertorius]

Right but if velocity is adequate those people are crazy for having such long guns. The 270/6.5 PRC route is enticing but I want a one and done rifle

Right but if velocity is adequate those people are crazy for toting around such long guns.

The 270/6.5 PRC route is enticing but I want a one and done rifle for medium to big game. I'd like to take shots at 500 with confidence even if it's not a perfect broadside shot. A 20 inch 7 PRC maintains 1500 ft lbs of energy out to 800 yards with 175 gr eld-x. Seems like a no brainer if you can handle the recoil. I deer hunt with a 9lbs 7 rem mag (my dad's rifle) and the recoil doesn't really bother me so I see no reason not to get the 7 PRC.

Planning on a 6 inch suppressor so I'll be right at 26".

Energy is not a good measure of terminal performance. There are several threads around here you should probably check out.

 

[BilboBaggins]

Energy is not a good measure of terminal performance. There are several threads around here you should probably check out.

Ok I'll check them out, I think I found one.
I do accept that a small bullet in the vitals is going to kill a large animal. However, more energy behind the bullet would just allow you to take shots you may not take with a less powerful cartridge. For example on quartering shots at long range I think more mass and velocity is useful for punching through non vital organs or joints, if necessary. Is that not the case?

 

[Taudisio]

This bear was wider, hide to hide, than any elk I have killed or put a knife into. Barrel is 20”, plus suppressor. Shot was 523y. You don’t need a magnum cartridge. Don’t shoot animals in the guts. Shooting more rounds in a session and going to the range more often, will help you become better at long range. Magnum cartridges only make that more difficult, on your shoulder and your wallet.