Velocity & muzzle blast from shortened barrel

[BradCoPAHunter]

I went to my local gun store the other day looking for a Ruger M77 for hunting black bears and deer.  One in particular stood out on the rack because the previous owner had the barrel shortened to 17 inches.  "Now," I thought, "that would be handy in the thick woods I hunt."  However, the gun was chambered in .30-06, and I imagine it would have a heck of a muzzle blast and recoil due to the shorter barrel and lighter weight.  I also wondered how much the velocity would be affected by the short barrel.  Anyone have experience with .30-06 or .308 class carbines, and what do you think of them?

[Mckie Hollow]

Ive been Hunting with a Model 7 - 18" -  Kevlar stock, for Years. One of the best carrying rifles Ive handeled. 5lbs. 4oz., without the Scope,Rings & Bases. As good as some of the more expensive light weights. You have to be very aware of a barrel shorter than 18"or 20". Can be dangerous if You happen to slip & Fall.

[jro45]

The velocity of a 18" barrel in 30/06 would be: With normal velocity being, with the 150 gr bullet,2950 FPS. It is 2670 FPS. Thats not to bad. But theres still that muzzel blast.

I figure 40 FPS loss per inch with normal being 24" barrel. There are some 22" barrels also.

[ScoutMan]

40 fps velocity loss is on the high side. For the shortened barrels you need the fast burning powders like IMR 3031. I'm just betting but I think you could get 2700 fps from an 06 150 gr. bullet from the Hornady " liight" magnums.

[tanoose]

Brad i wouldn't let the shorter barrel bother you so your 30/06 now becomes a 308 she will get the job done and like you said it will be very handi , i also have the m77 in 30/06 in the ultra light model w/20'"  i haven't chrony it yet but this is one of my favorite rifles.

[redhawk500]

Try the recommended highest velocity loads from the popular reloading manuals first.  In my limited experience with rifles of shorter and longer configurations, use the best loads for a 24 or 26 inch test barrel and you'll have a good starting place.  In my limited experience with .308 Winchester, 9.3x62mm and .375 H&H, the velocity loss, or even a slight gain from barrel to barrel is never going to be significant in the field.  In the 9.3x62mm my "loss" was in the low teens, not 40 fps per inch!  Remington used to publish a rule of thumb:  Take the velocity and shift the decimal two places to the left for an estimate:  2000 to 2500 expect 20 to 25 fps, 2500 to 3000 expect 25 to 30 fps and so on.  High bore to case volume ratio cases, like the .22 Long Rife in the extreme case, lose very little per inch.  The big case small bore magnums are the worst offenders in the muzzle blast / short barrel department.  Simple solution, don't get next to pine trees or other natural reflector, wear those hearing aid look-alike shooter's ears in the woods.  At my age, with years of working around motor generators and jet engines, I can hunt better when I can hear better.

[jro45]

The way I figure 40FPS loss is because I had a 22" barrel on my 30/06 that finally got shot out so I had a new barrel put on and it was 26" long. So then I fired 20 rounds thru my conagraph to get the FPS of that round witch my 22" barrel shot 160 fps slower. So I use that figure as an about. It comes out to 40 FPS per inch.

[Lone Star]

There is a lot of data available to let you know just what to expect in terms of velocity loss from short barrels. 

G&A Nov 1981 - the same barrel cut down in 2" increments:
30-06/165gr 
26" = 2896
24" = 2850
22" = 2820
20" = 2772
average = 20 fps/inch

G&A July 1989, the same barrel cut down:
.308 WCF - 165gr
22" = 2674
21" = 2636
20" = 2617
19" = 2595
averge = 26 fps/inch

The handgun silhouette guys proved long ago that for maximum velocities in short barels, use the same powders that give the maximum velocities in long barrels.  The old wives' tale that short barrels need faster powders is just that - a tale. 

From G&A Sept 1987, .308 with 180-grain bullet loaded to 52,000 psi, same barrel cut off in 2" increments:
Barrel...44.5gr/IMR4320....34.5gr/IMR4198
24"...........2700 fps..............2450 fps
22"...........2660 fps..............2420 fps
20"...........2620 fps..............2380 fps
18"...........2550 fps..............2340 fps
16"...........2480 fps..............2280 fps
14"...........2400 fps..............2230 fps
12"...........2300 fps..............2150 fps
10"...........2180 fps..............2050 fps

While faster powders lose the velocity race, they can provide lower muzzle blast and flash.  If these are more important to you than velocity, then load faster powders.  If two powders give about the same velocity in 24" barrels and one is faster burning than the other, it may be wise to choose the faster of the two or to chose the one with a flash retardent coating.

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[LEO]

I have a 16" barreled 308 and use it to deer hunt with, I shoot a 150 grain bullet and get a little over 2600 feet per second from it.  The blast is an issue when sighting in, the range I shoot at has covered benches, for practice away from the benchs or when hunting you really don't notice it.  For sighting in I just wear plugs and muffs, when practicing plugs only.  The deer I have shot with this rifle really didn't react any differently than deer shot with my 24" barreled 308 but the short one is a lot easier to get through the thick stuff with, easier to manage in a stand, or blind, and seems faster to the shoulder.  I would be more concerned with the quality of the crown of the rifle than the velocity or blast.  Good hunting

[dw06]

Lone Star has got it right,loss of 20-25fps per inch cut off.All I hunt with is a 20 inch remington 700 carbine in 30-06.Also have a 18 inch 308 in remington 600.As some have stated muzzle blast is only noticed when shooting off bench.I've opened allot of eyes at ranges over the years,comments such as that short barrel won't shoot to you lose too much velocity.Come time for shooting and I would not only shoot better groups,then proceed to match their trajectory out to 300 yards,as that was lenght of range,and they could'nt understand it.
Had a ruger ultra light in 06 with 20 barrel,and it would shoot.Nice to pack,but I let a guy talk me out of it.

[nomosendero]

Lone Star has got it right,loss of 20-25fps per inch cut off.All I hunt with is a 20 inch remington 700 carbine in 30-06.Also have a 18 inch 308 in remington 600.As some have stated muzzle blast is only noticed when shooting off bench.I've opened allot of eyes at ranges over the years,comments such as that short barrel won't shoot to you lose too much velocity.Come time for shooting and I would not only shoot better groups,then proceed to match their trajectory out to 300 yards,as that was lenght of range,and they could'nt understand it.
Had a ruger ultra light in 06 with 20 barrel,and it would shoot.Nice to pack,but I let a guy talk me out of it.

Well, Lone Stars info is accurate, but we are stretching things just a bit to say that we would lose 20FPS per inch right down to 17" as is being implied, I don't buy that. We are talking about a 30-06 going down to 17", not a 308. A 30-06 will lose at an increasing rate after 19" & to me an 18 is not too good in the 06 at all!

The 308, though has a different performance window due to smaller powder capacity in the same bore. I like the 20", but an 18 works fairly well,
& I have seen decent verlocities with these & even at 16" as Lone Star's post shows.

And the blast of a 17" barrel 06 would not be my idea of fun. I know what was said about not noticing it except from the bench, I don't feel a magnum when I am shooting game animals, etc., but if you aren't wearing hearing protection which hunting(few do), then your ears will get the damage as they don't know if you are hunting or not. 

I just don't see the purpose of a 17" '06. If I felt I needed a gun of that approx. length, I would buy a short action in 308 with an 18" barrel, the
gun would be the same length with less blast & recoil & very similar performance. But, to each his own.

[Slamfire]

Remington sold a lot of 74X carbines with 18" barrels in .30-06. Mostly to folks who ain't gun nuts. Worryin' about gittin' the last couple fps outa yore rifle, is what leads to trouble. Take what you can git with factory ammo, and use it as a guide for your handloads.  Wear some of the new earplugs that cut off sound above 80 or 90 decibels. 

[nomosendero]

Remington sold a lot of 74X carbines with 18" barrels in .30-06. Mostly to folks who ain't gun nuts. Worryin' about gittin' the last couple fps outa yore rifle, is what leads to trouble. Take what you can git with factory ammo, and use it as a guide for your handloads.  Wear some of the new earplugs that cut off sound above 80 or 90 decibels. 

Remington has done alot of weird stuff. They sold the 30-06 carbines, (actually 18.5") but they did not sell it in a 308, where the shortie would be more efficient & less blast & a better gun.  Gotta love that logic, about as good as the 350Mag with a shotgun style vent rib.

I agree about the ear protection, but again most won't do it & when it comes to muzzle blast, the 17" mentioned will be alot worse than the 18.5"
Remington carbines. I will let someone else shoot it.

 

[Lone Star]

...we are stretching things just a bit to say that we would lose 20FPS per inch right down to 17" as is being implied, I don't buy that. We are talking about a 30-06 going down to 17", not a 308. A 30-06 will lose at an increasing rate after 19" & to me an 18 is not too good in the 06 at all!

Sierra data indicates that going from a 26" barrel to a 15" barrel results in a 400 fps velocity loss - 36 fps/inch - when using IMR4064 powder.  This is close to the second set of .308 data I posted above - 30 fps/inch with IMR4320.  Both the .308 and the .30-06 give comparable performance in Sierra's 15" barrels, virtually identical considering all bullet weights.

They sold the 30-06 carbines, (actually 18.5") but they did not sell it in a 308, where the shortie would be more efficient & less blast & a better gun.  Gotta love that logic...

Considering that Remington is in business to sell rifles it would make perfect sense that they would take their best-selling chambering to offer in low-volume runs of carbines.  Gotta love the logic of actually trying to sell a firearm rather than trying to pander to a very few shooters who probably wouldn't buy their product anyway....

[nomosendero]

...we are stretching things just a bit to say that we would lose 20FPS per inch right down to 17" as is being implied, I don't buy that. We are talking about a 30-06 going down to 17", not a 308. A 30-06 will lose at an increasing rate after 19" & to me an 18 is not too good in the 06 at all!

Sierra data indicates that going from a 26" barrel to a 15" barrel results in a 400 fps velocity loss - 36 fps/inch - when using IMR4064 powder.  This is close to the second set of .308 data I posted above - 30 fps/inch with IMR4320.  Both the .308 and the .30-06 give comparable performance in Sierra's 15" barrels, virtually identical considering all bullet weights.

They sold the 30-06 carbines, (actually 18.5") but they did not sell it in a 308, where the shortie would be more efficient & less blast & a better gun.  Gotta love that logic...

Considering that Remington is in business to sell rifles it would make perfect sense that they would take their best-selling chambering to offer in low-volume runs of carbines.  Gotta love the logic of actually trying to sell a firearm rather than trying to pander to a very few shooters who probably wouldn't buy their product anyway....

Actually, I was backing up your data that you posted. When I mentioned the implication or leap that the data would apply to the 30-06, someone else was trying to make that tie, not you in my view. I would not want a 26" personally in a bolt gun, so no need looking at a 400fps loss, which is huge. So in normal length barrels we are looking at 200fps loss, more than I am willing to give up, & thanks for pointing that out with the 36fps PER INCH data. Not to mention the blast, which is more than I want & I shoot magnums quite a bit

And no, I was not talking about Rem. being goofy for offering the 18.5" '06 since it is the best selling cal. (although 20" would be better). Rather I feel it is silly to offer the '06 & not offer it in the more logical 308. Why not both? I don't think it is pandering if you offer a better set-up & then market it. Sorry, but I am a Rem. fan & I have more Rems in my safe than any other, but I can recognize their stupid moves as well as their smart ones. I would come alot closer to buying the 308 pump with a 18.5 than a '06, in fact I have been in a few campfire discussions on that one & I am not alone.

Again, why not get something like a 308 Model 7 with a 20" with the same performance, less blast & recoil than a 17" '06?

[RaySendero]

Just got a Rem 700P LTR in 308.  It has a 20" barrel.  Sighted it in with Fed 165 vital shocks - On the box velocity was stated at 2,700 with 24" barrel.  It averaged 2,510 on my chrono.  That's almost 50 fpspi if the claimed velocity on box could be believed.

[nomosendero]

Ray, the 700P LTR seems pretty neat to me. Other than the vel., how do you like it.

[RaySendero]

Ray, the 700P LTR seems pretty neat to me. Other than the vel., how do you like it.

So far, so good!  Got a hunting trip planned next weekend will update you afterwards.

[RaySendero]

Ray, the 700P LTR seems pretty neat to me. Other than the vel., how do you like it.

So far, so good!  Got a hunting trip planned next weekend will update you afterwards.

Harvested two does with rifle last weekend.  The Fed. 165 vital shocks made two holes in both deer - One also broke a leg bone up near shoulder. 

[nomosendero]

Sounds good & thanks for the info!!

[Curt Dawson]

I used to shoot a 16" barreled 1917 enfield in 30-06.Did not have chrono;so do not know what the velocity was.accuracy was vey good runnig between 3/4"-2" for 5 shots at 100yds.Muzzle blast was impressive especially from the prone position.I hope to get another on some day.

[Bug]

Well, just to throw my two cents in;
 I have a M-7 in .308 that came with an 18 1/2" barrel. Thinking I would up the velocity, I screwed on a 22" barrel from a M-700. I gained a whopping 50fps with the exact same load. I realize this is purely anecdotal, and a sample of one. Ever since, I have been considering putting the 18 1/2" barrel back on. I have delayed though, because the 22" barrel shoots tighter groups. Yeah, about 1/2" tighter.    Just about the same (read NONE!) practical difference in the real world.
  I really wish I could stop obsessing about that last 100fps, or that last 1/4". 

[USMC0332]

Guns&Ammo ran an article a few months ago about this same subject. It had good data. In some charted loadings the shorter barrel actually was faster. I agreed with the article and the article on the Ruger Frontier(I really want one of these). In the woods, the actual performance between a long barrel and a short one would most likely not be noticed. Carrying a rifle with a 26 inch barrel as compared to a 16.5 inch Ruger Frontier would definately be noticed. The short barrels are also accurate. I am definately a fan of carbine length rifles. I just enjoy carrying them. Since while hunting I carry more than bench rest, they make me happy. I hunt with guys with .300 Weatherbys with 26 inch barrels with muzzle brakes on them. They sure seem awkward to me. It is a good thing that we all can carry rifles that please our own selves. Now if we all just had a lot more days per year to carry them in the field.

[nomosendero]

I think I will hold off cutting my barrels down so that they will be faster for a day or two. 

Guns & Ammo is all about selling magazines. If you watch, in a month or 2 they will likely tell us that the long barrels make good gains & we had better get one, they have done this stuff for years. They do the same with Magnum vs standard cartridges, what scope power you use, you name it. It is very possible that they wanted to promote the stubby little Ruger barrel ,as a favor at that moment.
Who cares, if someone thinks the 16.5" tube will be faster than a 10" longer barrel, they deserve whatever gun they buy. I do like a 20" barrel for a modest case like a 308 for a woods gun, it's OK, but I sure don't think it is faster than a 24"

[Lone Star]

Now now, it isn't all about G&A selling magazines.     In their support, Speer #13 states in their Lab Notes on page 281 that they got higher velocities with their .308 loads than they did with their .30-06 loads.  And when testing their .308 loads their 22" velocity barrel gave higher velocities   than their 24" pressure barrel did.   Common sense says these experiences aren't possible - but Speer describes how it happens.  Me, I wouldn't count on it.


.

[nomosendero]

Now now, it isn't all about G&A selling magazines.     In their support, Speer #13 states in their Lab Notes on page 281 that they got higher velocities with their .308 loads than they did with their .30-06 loads.  And when testing their .308 loads their 22" velocity barrel gave higher velocities   than their 24" pressure barrel did.   Common sense says these experiences aren't possible - but Speer describes how it happens.  Me, I wouldn't count on it.


.

Me, I don't think I would count on it either.        Those who have shot a little & not just read alot know that we have fast barrels, slow barrels & an exception here & there. And it would be a wonderful World if a 30-06 was faster than a 300WM & a 308 was faster than a 30-06, other than the fact that no one would know why the bigger rounds exist. And it would be great if the 16.5" tube was faster than a 26", wow.
If both the smaller rounds & the shorter barrel were faster, I could just load up my Super 14 30-30 & it would be faster than my 300WM with it's 26" tube!!! 

If someone really wants to look at how barrel length affects velocity with a modest case capacity like the 308,
go to   www.6mmbr.com   .  Click on the 308 topic & they have a detailed chart of velocities with barrels of
20"-32". The chart shows a loss of 140FPS from a 20"-26". To me, that is a good trade off & the 20" makes sense for a hunting rifle & I like a 24" in a tactical/Target 308. If you get shorter, the 18 is OK, to me the 16.5" give up too much. Under 20" & the blast is too much.

Of course, with the bigger cases, you will lose more per inch in rounds like the 300 Mag. Just common sense stuff, really.

[USMC0332]

I was rereading a recent Handloader magazine today. There was a good article about this subject. It pretty much stated that there is no rule regarding length. Quite a few guns lose around 25fps per inch. Some loads and barrels lose more, some less.

[nomosendero]

I was rereading a recent Handloader magazine today. There was a good article about this subject. It pretty much stated that there is no rule regarding length. Quite a few guns lose around 25fps per inch. Some loads and barrels lose more, some less.

Yep.