Velocity Loss With Shorter Barrels

CoElkHunter

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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.
I would imagine any of the faster magnums (.264WM, 7mm RM, .300WM, etc.) would have similar velocity losses going from 26” to a 22” barrel as the .338WM? Maybe the magnums with fatter cases (Ruger, RUM, WSM, etc), don’t suffer the same velocity loss due to more efficient burning of the powder in shorter barrels? I need to buy a chronograph!
 

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I would imagine any of the faster magnums (.264WM, 7mm RM, .300WM, etc.) would have similar velocity losses going from 26” to a 22” barrel as the .338WM? Maybe the magnums with fatter cases (Ruger, RUM, WSM, etc), don’t suffer the same velocity loss due to more efficient burning of the powder in shorter barrels? I need to buy a chronograph!
I have a 20" and 23" .375 Ruger. 22 fps is the average per inch difference. When the weather clears up, I have some RL16 and 17 to test with some 300 grain RN bullets a member here donated for the test.
 

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I am a fan of longer barrels. There is a mania for short hunting gear, and I certainly won't argue with people who are in the thickets somewhere and really need a handy rifle. But it seems to have no downward limit. When I started bow hunting the average compound bow was 48 inches long, and 52 was the popular upper limit. Today that has probably dropped to 32 inches while the low end is around 28. As a trad archer, the same phenom was happening as we dropped from 72 to 48 inches, though there are practical problem with trad gear. I do wonder how trad archers leave the house or get any game with bows that average longer than any compound bow was ever built.

Same thing with rifles. In Canada it is hard to get a lot of guns with barrels longer than 18 inches, and we don't allow silencers either. This is partially driven by the fact that the majority of shooters no longer hunt, and wear muffs all the time.

Shorter barrels mean more blast, and that blast is nearer your ears. Given the damage to hearing is proportional to the square of distance x the increased blast, it is not insignificant. And then we have muzzle brakes popping up.

Even a counter bore at the muzzle is a sort of linear brake, and worth considering.
 

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Wow! That’s almost no velocity loss! But I would have kept the barrel at 24”. I personally like longer barrels. Better sight plane? I also like 28” vs 26” barreled shotguns. Just personal preference?
Pointability. I thought my 28" barrel shotgun was too long until I tried it on ducks.
 

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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.

Calculated loss does not always = actual loss so my question stands.

That is absolutely pure bullshit about no powder coming out the barrel. Got no idea where you got that rubbish from. Unburnt powder does come out the end of the barrel. What do you think makes a lot of the flame seen, unburnt powder burning in the air. Try this. Get a 20" barreled 308. Put a sheet on the ground and hang a sheet just short of the end of that. The burn marks on them are from unburnt powder. You can, with some powders, find unburnt powder on the sheet. Proven many times. Sit at a bench on any range and if the person next to you has a short barrel, especially with a break on it. and it is not uncommon to have powder from that rifle on your table. Happened more than once to me.

Where in Australia are you allowed suppressors??? Do you always use a suppressor if not do you always re zero after using one?
 

Rule 303

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I would imagine any of the faster magnums (.264WM, 7mm RM, .300WM, etc.) would have similar velocity losses going from 26” to a 22” barrel as the .338WM? Maybe the magnums with fatter cases (Ruger, RUM, WSM, etc), don’t suffer the same velocity loss due to more efficient burning of the powder in shorter barrels? I need to buy a chronograph!

I use to think similar and went off published figures. Then I bought a Chronograph and found most were close but there were big differences sometimes. I discovered that different powders in the same firearm could give larger discrepancies. Also the smaller the calibre the greater the loss. Another thing I wonder about is the actual barrel as in a slow or fast barrel what results will they produce. Remington use to claim that V Loss was around 50FPS per inch of barrel chopped for slower cartridges e.g 308 and upto 100fps for faster cartridges. I guess even primers may have an effect.

This is why I do not go off calculated figures but rely on the Chrony unless I am only wandering/speculating.
 

CoElkHunter

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I use to think similar and went off published figures. Then I bought a Chronograph and found most were close but there were big differences sometimes. I discovered that different powders in the same firearm could give larger discrepancies. Also the smaller the calibre the greater the loss. Another thing I wonder about is the actual barrel as in a slow or fast barrel what results will they produce. Remington use to claim that V Loss was around 50FPS per inch of barrel chopped for slower cartridges e.g 308 and upto 100fps for faster cartridges. I guess even primers may have an effect.

This is why I do not go off calculated figures but rely on the Chrony unless I am only wandering/speculating.
Good points! I’m just curious as to why it seems the fatter cased cartridges seem to achieve the same velocities in shorter barrels as compared to their contemporaries which need longer barrels to achieve the same velocities. I.e the .375 or .416 Ruger cartridges with 20” barrels vs. a .375 h and h or .416 RM, which SEEM to need longer barrels to achieve the same velocities? The velocity difference may be moot, but you don’t see many/any of the latter cartridges with 20” barrels. I’m surmising the powder burn is more efficient in the shorter/fatter cased cartridges? I still prefer longer barrels, so it’s a moot point for me personally.
 

austrianhunter

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Calculated loss does not always = actual loss so my question stands.

That is absolutely pure bullshit about no powder coming out the barrel. Got no idea where you got that rubbish from. Unburnt powder does come out the end of the barrel. What do you think makes a lot of the flame seen, unburnt powder burning in the air. Try this. Get a 20" barreled 308. Put a sheet on the ground and hang a sheet just short of the end of that. The burn marks on them are from unburnt powder. You can, with some powders, find unburnt powder on the sheet. Proven many times. Sit at a bench on any range and if the person next to you has a short barrel, especially with a break on it. and it is not uncommon to have powder from that rifle on your table. Happened more than once to me.

Where in Australia are you allowed suppressors??? Do you always use a suppressor if not do you always re zero after using one?

Calling FACTS bullshit and rubbish and Not beeing able to know the difference between austria and australia is a good start. ‍♂️
most of the powder will burn in the barrel - only some flakes or kernels leave the barrel. Most of the time this happens on low pressure reloads.

Powder is a chemical compound that does not need ambient air to burn - muzzle flash is a re-ignition of hot gases. There are enough high speed vids of bullets leaving the barrel - so proof your own bullshit.

The Steyr Factory is near my place - they did tests with FIVE piezo sensors over the whole barrel length. Pressure is WAY higher in the chamber and drops very fast the farer you are from chamber - doestn matter if bullet still in barrel or not. Also calculated will show same results.

GRT calculated velocity loss is the same as measured with a Mehl BMC 19 to single digit differences.
 

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I prefer to stay with standard lengths 24" for bushveld and 26" for longer range magnums
 

Philip Glass

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I'm sure like many other topics here on AH, this topic has been examined over and over. But I haven't been able to find anything here recently. If someone has a link to a thread here regarding this topic, I would welcome it. Specifically, velocity loss with a .458WM, .416 Remington Mag, .416 Taylor and .375 H and H with barrels from 25" to 22". I know some cartridges like the .375 and .416 Rugers plus the B & Ms were designed to obtain maximum velocities with 20" or shorter barrels, but what about the older designed cartridges? And is the velocity loss of any REAL WORLD hunting significance? Thanks!
I am cutting my new .300 Win mag barrel down to 22” and threading it. I’ve heard that adding a suppressor actually adds a bit of velocity. I’ve been hearing of many even with custom guns going with shorter barrels lately. I’d like to hear what the guru’s say about it.
Regards
Philip
 

Viral_SIGness

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I am cutting my new .300 Win mag barrel down to 22” and threading it. I’ve heard that adding a suppressor actually adds a bit of velocity. I’ve been hearing of many even with custom guns going with shorter barrels lately. I’d like to hear what the guru’s say about it.
Regards
Philip
 

lwaters

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I feel that you would be better off with a 22in. 30-06
I am cutting my new .300 Win mag barrel down to 22” and threading it. I’ve heard that adding a suppressor actually adds a bit of velocity. I’ve been hearing of many even with custom guns going with shorter barrels lately. I’d like to hear what the guru’s say about it.
Regards
Philip
 

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I recently had to have my 1974 Parker Hale 7mm REM re-crowned (due to a terrible muzzle break job done years ago). Meanwhile, due to the supply issues, I had to switch to 150 gr Barnes ttsx. So, I went through the process of working up new loads with the shorter 22" barrel. I ran it all through the Chrony, and I figure I lost about 70 fps./inch. I ended up with the max recommended, (63.1 gr H4831) and I can only get 2828 fps. Not only do I hope that is fast enough, it has to be! Other than Retumbo, its the only powder I own.

A couple of side notes;
It doesn't (and never did!) need a muzzle break. I find this max load almost pleasant to shoot (especially after shooting the .416 Rigby). Besides, it's all I can ask of the old girl...
Interestingly, each time I started with a cold barrel, that first shot averaged 75 fps slower! That's a lot, more than I realized, when it's already going kind-a slow.
 

CoElkHunter

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Very interesting test report. I would’ve thought the velocity loss would have been greater? But, I’m staying with my 24-26” barrels, although my .416 Taylor has a 22” barrel and I’m comfortable with that length also.
 

Viral_SIGness

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Very interesting test report. I would’ve thought the velocity loss would have been greater? But, I’m staying with my 24-26” barrels, although my .416 Taylor has a 22” barrel and I’m comfortable with that length also.
I went to a lot of trouble to get a Ruger African, because I thought my Alaskan was sub-par. Should have seen my face when I realized 22 fps per inch is all I gained.
 

CoElkHunter

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I went to a lot of trouble to get a Ruger African, because I thought my Alaskan was sub-par. Should have seen my face when I realized 22 fps per inch is all I gained.
Again, the Ruger cartridges were designed for shorter barrels so that minimal velocity loss isn’t surprising. I was surprised that in the barrel test report you provided, the velocity loss wasn’t more significant with the .300WM? ALTHOUGH, if one could extrapolate from that test, the velocity loss from a 26” to a 22” at around 200fps loss, that would be somewhat significant and now in the realm of .30-06 velocities?
 

IdaRam

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I am cutting my new .300 Win mag barrel down to 22” and threading it. I’ve heard that adding a suppressor actually adds a bit of velocity. I’ve been hearing of many even with custom guns going with shorter barrels lately. I’d like to hear what the guru’s say about it.
Regards
Philip
Adding a suppressor will usually add a little velocity, known as free-bore boost. Probably around 50-75 fps. Not unheard of to enhance accuracy slightly as well.
With a .300 WM, generally speaking, you can plan on about 35-50 fps per inch of barrel in velocity loss.
Philip, what suppressor did you end up going with?
 
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Philip Glass

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Adding a suppressor will usually add a little velocity, known as free-bore boost. Probably around 50-75 fps. Not unheard of to enhance accuracy slightly as well.
With a .300 WM, generally speaking, you can plan on about 35-50 fps per inch of barrel in velocity loss.
Phillip, what suppressor did you end up going with?
Thank you so much for the info. I was thinking it was about what you mention. I got the Thunderbeast Ultra 5. It is just about the smallest .30 cal suppressor on the market. Great for hunting but being small it will not be the best suppressor. I really like it and it will go with me and my group to the Eastern Cape in July.
 

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That is a great can, especially for a hunting rifle. Have fun on that trip in July!
I am headed to Mozambique in August and already chomping at the bit.
 

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