Velocity Loss With Shorter Barrels

[Rule 303]

I have no issues with a 21” bbld.375 H&H. I suspect that you would not want to go much shorter.

Be interesting to see how much if any unburnt powder is coming out the barrel.

 

[Rule 303]

Blast was horrible on this 16.25" 308. I put on a BRT (Black river tactical) covert comp. It directs blast forwards and works like a charm. Admittedly it may not look the best on a standard hunting rifle. View attachment 330383

Considering a 20" barreled 308 spits out some unburnt powder you would be losing a fair bit. I take it you use a fast burn rate powder.

 

[CoElkHunter]

Be interesting to see how much if any unburnt powder is coming out the barrel.

Yes, with a slower burning powder generally used in this cartridge, I was wondering the same thing?

 

[WAB]

Yes, with a slower burning powder generally used in this cartridge, I was wondering the same thing?

I use H-414. I’ve looked carefully and not found any. I’ve also checked velocities with multiple chronographs. I must be right on the edge.

 

[CoElkHunter]

I use H-414. I’ve looked carefully and not found any. I’ve also checked velocities with multiple chronographs. I must be right on the edge.

Your good to go then!

 

[CoElkHunter]

Cope with a 26 inch barrel especially in scrub country.
Bugger my fat thumb

However a 24 inch barrel is a reasonable compromise.
I had a 308 with a 20 inch barrel and the blast was something horrendous.
In my Sako rifles the barrel length is around 23 inch in the 270 and 24 inches in bigger calibers.

I’ve been through some pretty thick forest type stuff with my 26” barreled Browning .338 with no problems. Actually, the length of the barrel was the least of what was a hindrance. Backpack and sling were/are more of a bush catcher. But I agree, a 24 “ barrel is probably an ideal compromise.

 

[John J]

Considering a 20" barreled 308 spits out some unburnt powder you would be losing a fair bit. I take it you use a fast burn rate powder.

Barnes factory ammo 150 gr TTSX 2900 fps box velocity. 10' from muzzle chrono 2700 fps. Unburnt powder if any does exit. I dont see any signs of unburnt powder.

 

[Rule 303]

Barnes factory ammo 150 gr TTSX 2900 fps box velocity. 10' from muzzle chrono 2700 fps. Unburnt powder if any does exit. I dont see any signs of unburnt powder.

After reading of an experiment to find out I did the same thing with a 20" barreled 308. Laid a sheet on the ground and hung one vertically at the end of the sheet on the ground. I found burnt powder marks on both sheets and the odd bit of unburnt powder. This shows a bit of unburnt powder came out of the barrel. If I used a faster powder maybe non would have made the sheets. I see you are getting 200fps less than advertised, I would think that not all the powder is being burnt in the barrel.

 

[Rule 303]

I use H-414. I’ve looked carefully and not found any. I’ve also checked velocities with multiple chronographs. I must be right on the edge.

I use AR2209 the Aussie powder with the same or about same burn rate. H4350 is AR2209.
When running the Woodleigh Hydros I use AR2206H/H4895 as I can't get enough 2209 in the case.

 

[Standard Velocity]

Blast was horrible on this 16.25" 308. I put on a BRT (Black river tactical) covert comp. It directs blast forwards and works like a charm. Admittedly it may not look the best on a standard hunting rifle. View attachment 330383

I generally prefer not to put things on the end of a barrel but these devices work well. I put a Levang linear compensator on a .22 and everyone thought I had a tiny suppressor.

The linear compensators simply redirect blast towards the target. I’m not too worried if the thing I’m shooting at hears the shot. Since standard cartridges have a manageable level of recoil for most people, redirecting the noise is probably more beneficial than reducing recoil.

 

[nztimb]

I do understand shortening to add a suppressor although cutting it short to gain "handiness" and then to put something on the end to reduce some of the effects of that shortness that takes it back to a longer length again is another matter again.

 

[Standard Velocity]

I do understand shortening to add a suppressor although cutting it short to gain "handiness" and then to put something on the end to reduce some of the effects of that shortness that takes it back to a longer length again is another matter again.

To me the benefit would only be on a sub 20” barrel. Some cartridges loose very little when run through short barrels but do become exponentially louder. Two steps forward+one step back=net gain. The only downside is having a thing dangling off the end of the barrel. IMO ugly.

 

[John J]

For me it was necessary. The short barrel is factory and the muzzle break was horrible, like getting slapped in the face every trigger pull from the blast. The comp negates that and protects the crown. It is a hunting rifle so its unloaded and muzzle down on a floor board alot. As for the look it fits the rifle I think. A more traditional rifle it would probably ruin the aesthetics.

 

[deewayne2003]

I had heard the "100fps per inch rule" back when I was developing loads for my .257Wby.

I chronographed my hand load and factory load out of the 26" barrel and both were 3,600fps. (Weatherby 100gr. TSX & Handload was 100gr. TSX with R22)

Then I sent the rifle off and had the barrel cut to 24" and chronographed rounds from the exam 2 boxes of ammo I did before...... End result 3,550fps

So I took 2" off the barrel and lost 50fps - from a cartridge over 3,500fps

So I would not be worried with velocity reduction in your case.

 

[austrianhunter]

Short barrels arent a big problem today. My 450 Rigby is 22“

I cut back my .338 WM from 24“ to 20“ with a minimal loss of Speed. Same with 9,3x62 - from 22“ back to 18,5“. The 8x57 got cut to 16“ instead of the factory 22“

The „longer“ barrels for 7x64, 6,5x55 and .22-250 are 22“

 

[USMA84DAB]

AustrianHunter - how do you like the way that your shortened rifles handle now?

 

[WAB]

My .458 Lott has a 22” bbl. I get 2300 fps with federal 500 gr factory ammo. My PH has his M70 in .458 Lott cut to 20”. I don’t know what velocity he is getting but he is very effective with it.

 

[Rule 303]

Short barrels arent a big problem today. My 450 Rigby is 22“

I cut back my .338 WM from 24“ to 20“ with a minimal loss of Speed. Same with 9,3x62 - from 22“ back to 18,5“. The 8x57 got cut to 16“ instead of the factory 22“

The „longer“ barrels for 7x64, 6,5x55 and .22-250 are 22“

What exactly are the velocity losses? How much more bark do you get from the shorter barrels.

I have a 200fps loss in my 308 when shot from a 20" barrel compared with my 22" barrel when using 155 grain projectiles. So unless I am restricting my shots to under 150mts that is a bit more of a loss than what I would want or expect from loosing 2" of barrel. The loss is greater with 130grain projectiles.

Yet with a 35Whelen the loss between 24" and 22" was barely 100fps. I would expect a 338win to loose at least 200fps with a 4" loss of barrel length and it would I suspect bark a lot more. Probably a lot of unburnt powder going out the end.

 

[austrianhunter]

What exactly are the velocity losses? How much more bark do you get from the shorter barrels.

I have a 200fps loss in my 308 when shot from a 20" barrel compared with my 22" barrel when using 155 grain projectiles. So unless I am restricting my shots to under 150mts that is a bit more of a loss than what I would want or expect from loosing 2" of barrel. The loss is greater with 130grain projectiles.

Yet with a 35Whelen the loss between 24" and 22" was barely 100fps. I would expect a 338win to loose at least 200fps with a 4" loss of barrel length and it would I suspect bark a lot more. Probably a lot of unburnt powder going out the end.

you can calculate loss in GRT - the amount of loss matches to single digit numbers my measurements.

unburnt powder very seldom leaves the barrel, cause powder burns near the chamber. so even if you dont have 100% of burn, powder stays in barrel and burns there until its gone.

i dont care about bark - there are suppressors.

 

[austrianhunter]

AustrianHunter - how do you like the way that your shortened rifles handle now?

there is no need for long barrels if you dont want to shoot the moon. shorter handles way better - especially with added suppressors. if you cut it shorter, you can go with a thicker barrel at same weight. short and thick is stable - better groups or less tricky with different loads.