18" .30-06?

[Gtscotty]

Who's done it, and what kind of velocities are you getting?

I'll head off the 'just go with a .308 if you're going that short" comments with I've had 18" and 18.5" .308s and they just don't have the capacity to deliver the kind of heavier bullet performance I'd like for this specific purpose.

Context: I just ordered a lightweight .30 cal suppressor specifically for use while hunting elk, so now I'm entering into the 12 month waiting stage where I brainstorm hosts. Both of my main hunting rifles have fairly thin barrels and therefore can not take a standard 5/8"x24 thread and still have sufficient shoulder without being cut down quite a bit. I have very good loads for both of them, so I'm hesitant to start chopping off large sections of barrel.

It occurred to me earlier while reading another thread that assuming the often cited 25 fps/in loss, a load that hits 2,800 fps in my current 22" .30-06 might be somewhere near or approaching 2,700 fps in a chopped 18" .30-06. With my 7" suppressor attached, such a beast would have an overall length similar to a long action with a 25" barrel... a bit dangly, buy not too bad in open country. I know it would be blasty, but this specific rifle would only really be shot with the can on, or at the range where I double up on earpro everytime regardless.

Thoughts? Has anyone gone this route? What kind of performance are folks seeing out of stumpy .30-06s.

 

[RPRNY]

My overwhelming objection would be blast and noise. Those don't figure in your equation. So, lead on McDuff.

I have an 18" M49 Persian Mauser sporter in 8 x 57. It's an apples to oranges comparison, but there are some learnings. The velocity loss is not necessarily linear. The best loads in my M49 are only 100 fps behind my 23" VZ-24. Bore and throat tolerances may factor. The point is that I assumed faster powders would be "better" in the shorter barrel. Several people suggested that was not true, but I did not listen. After much testing I found that medium to slower powders that worked best in the 23" barrel also worked well in the 18" barrel, with one exception. You will have the further complication of a supressor.

I would counsel the following:. Try several tried and tested mainstream 30-06 loads in 4350 with 165 grs, whatever RL works best, Varget, and IMR 4064. I think you'll be surprised by good old 4064, but I'm speculating. You may also find you get better relative velocity from heavier for caliber bullets, so I would do the same with 180 grs But I've no idea what impact a can will have...

Sounds like a cool project.

 

[eastbank]

i hunt in the thick woods in pa. most of the time and most of my shots are well under 200 yards and i have killed a pile of deer with this rem 7600 carbine in 3006 with a 2x7 leupold scope and imr-4350-55grs and a 165gr nosler BT. 2650-2700 fps and very accurett in my rifle. the left target is 180gr factory and the right target is my reloads, both shot from a bench rest. i put rem model 6 wood on my 7600 for the higher comb for scope use. eastbank.

 

[Salmoneye]

I have a Rem 7400 carbine (18") in .30-06 that gets used in the woods of Vermont...

Love it, but it is loud...

Have not put it over a chronograph in over 25 years, but I seem to remember that I was getting about 100fps less than my Father's longer barreled 742...That would have been with 180gr bullets...

Wish I could help more...

 

[jmr40]

About 100-150 fps less than a 22-24" barrel is about right with most loads. I've chronographed loads from a couple of different 20" 30-06 rifles and my brother had an 18.5" gun for a while, I was about 100 fps slower at 20". The 18" gun was before I owned a chronograph.

I know you said no 308, but I think you need to re-evaluate your last experience. From 22-24" barrels 30-06 will be 100-150 fps faster. Both lose speed when barrels are cut shorter, but the 308 loses LESS. By the time you get to 18" I'd expect the 30-06 to only have about 50 fps advantage. I'm still getting almost 2600 fps with 180's from my 18" 308. That is elk medicine out past 400 yards. I've seen individual guns that were as much as 130 fps slower than other guns with the same length barrel. I think it possible you may have had an experience with a slow barrel and blamed it on a short barrel.

Most people just don't consider shooting heavy bullets from 308, but it works better than you may think. I know of some guys shooting 215 gr bullets from 20" 308 at targets at over a mile.

If it were me, I'd spend $350 for the 18" Ruger Predator in 308 The barrel is already the length you want, it is already threaded for a can, you won't have to modify and potentially ruin a proven rifle that you already have, you'll have less muzzle blast, and you spend less buying a new rifle than modifying one that you have.

But some guys just like to tinker around with stuff. Nothing wrong with that either.

 

[stiab]

Have two .30-06 carbines, a Ruger and a Remington, but have not run either thru the chrono. Did kill a deer with the Ruger, and in shooting both have not noticed any additional noise or muzzle blast. It may be there, just not noticing it.

 

[Llama Bob]

You can definitely do what you want to do, and velocity loss will be limited. With a 200 grainer you should be able to get 2500 ft/s with RL-26, RL-17, RL-16, Ramshot Hunter, H414, Vihtavuori N550, W760, Accurate 4350 and IMR 7828 SSC.

At 180gr, you can get 2650 with more or less the same list except IMR 7828 SSC is not longer an option - too slow.

 

[Gtscotty]

i hunt in the thick woods in pa. most of the time and most of my shots are well under 200 yards and i have killed a pile of deer with this rem 7600 carbine in 3006 with a 2x7 leupold scope and imr-4350-55grs and a 165gr nosler BT. 2650-2700 fps and very accurett in my rifle. the left target is 180gr factory and the right target is my reloads, both shot from a bench rest. i put rem model 6 wood on my 7600 for the higher comb for scope use. eastbank.

Nice looking rifle, for some reason when I was first thinking about this I didn't even think about all the short 7600 carbines in .30-06 that have been and still are being used.

I know you said no 308, but I think you need to re-evaluate your last experience. From 22-24" barrels 30-06 will be 100-150 fps faster. Both lose speed when barrels are cut shorter, but the 308 loses LESS. By the time you get to 18" I'd expect the 30-06 to only have about 50 fps advantage. I'm still getting almost 2600 fps with 180's from my 18" 308. That is elk medicine out past 400 yards. I've seen individual guns that were as much as 130 fps slower than other guns with the same length barrel. I think it possible you may have had an experience with a slow barrel and blamed it on a short barrel.

Most people just don't consider shooting heavy bullets from 308, but it works better than you may think. I know of some guys shooting 215 gr bullets from 20" 308 at targets at over a mile.

If it were me, I'd spend $350 for the 18" Ruger Predator in 308 The barrel is already the length you want, it is already threaded for a can, you won't have to modify and potentially ruin a proven rifle that you already have, you'll have less muzzle blast, and you spend less buying a new rifle than modifying one that you have.

I don't claim to be an expert at anything, but I have loaded for an 18" .308, an 18.5" .308, a 20" .308, and two 22" .308s, I have a decent idea of what a .308 will do. What I don't have, and what I asked for here was experience with 18" .30-06's. In similar 22" barreled rifles I've generally seen a 150 fps to 200 fps velocity difference in the heavier bullets between .308 and .30-06. You stated that the .308 loses less velocity with a shorter barrel than the .30-06, and by the time they are at 18", there is only a 50 fps difference. How do you know this? Have you measured it? If the 25 fps/in generalization is more or less accurate going from 22" to 18" barrels, then some of the 180gr loads that clock 2,800 - 2,840 fps in my 22" 30-06 should be around 2,700 in an 18" .30-06. If you are running 2,550 out of your Predator, that is still a 150 fps difference, not the 50 fps difference cited. I know heavier bullets can be shot from .308's, I shoot them.

I'm not worried about efficiency or burning a bit of extra powder or blast, this would be a suppressed hunting rifle probably a Tikka, where action length and weight would be the same anyway. I already load for both. I don't see any pro's to the .308 in this situation that I'm not willing to trade for a bit of extra velocity on the 180 gr Accubonds. As for the Predator, I love my RPR with the same action, but its unfortunate that Ruger opted for a safety setup where the safety doesn't lock the bolt, that's one of my basic requirements for a hiking hunting rifle.

You can definitely do what you want to do, and velocity loss will be limited. With a 200 grainer you should be able to get 2500 ft/s with RL-26, RL-17, RL-16, Ramshot Hunter, H414, Vihtavuori N550, W760, Accurate 4350 and IMR 7828 SSC.

At 180gr, you can get 2650 with more or less the same list except IMR 7828 SSC is not longer an option - too slow.

That's pretty much what I'm thinking, I would probably use RL-16 or H4350, both of which I have had good accuracy and stout velocities with. If I can get the power of a 24" fully loaded .308 out of an 18" suppressed .30-06, I'd be pretty happy.

As an aside, I've had such good luck with RL-16 in a few different chamberings, I'd love to try RL-26 with 150 gr NPTs and 140 gr NABs in my .270. I've read about folks getting 3,000 fps+ with 150's out of 22" barrels, but unfortunately RL-26 is pretty much impossible to find live and in person around here.

 

[RecoilRob]

If I can get the power of a 24" fully loaded .308 out of an 18" suppressed .30-06, I'd be pretty happy.

.

How could that be possible? Both cartridges max out about the same pressures and shortening the barrel takes away the primary advantage the -06 has over the 308...being it's extra capacity to hold more slower burning powder which then does allow it to exceed the smaller case in a long enough barrel. The 308 doesn't use the longer barrel as well as the -06, but still does gain some velocity so it would be very surprising to see you match a 24" with the 18"er.

And how is the supressor going to like the additional muzzle blast of the higher powder charge? My only -06 is an Encore pistol with 15" barrel...and it really barks. Not saying it can't be done, but a can on that thing would have its' work cut out for it trying to muzzle the blast. Best of luck to you.

 

[Llama Bob]

Both .30-06 and .308 have nearly identical falloff per inch of barrel length. The ballistic advantage of .30-06 is very small (50-150 ft/s) comparing best loads to best loads, but that advantage stays basically unchanged as you shorten the barrel.

 

[Llama Bob]

With a 180gr A-Frame

24" Barrel:
-----------------
.308 max-SAAMI-pressure velocity (RL-17): 2744 ft/s
.30-06 (RL-26): 2889 ft/s

18" Barrel:
-----------------
.308 (RL-17): 2604 ft/s (140 ft/s loss)
.30-06 (RL-26): 2686 ft/s (203 ft/s loss)

 

[Gtscotty]

How could that be possible? Both cartridges max out about the same pressures and shortening the barrel takes away the primary advantage the -06 has over the 308...being it's extra capacity to hold more slower burning powder which then does allow it to exceed the smaller case in a long enough barrel.

The powder in either case is burned before the first few inches of bullet travel. The powders best for the .30-06 are slower, on a comparative scale, but they certainly aren't still burning at the 18" mark. With the .30-06 you have a larger area under the pressure curve, analagous to total force exerted on the bullet, that's true with 24" barrels or 18" barrels, it's just with the 18" barrel you are truncating the tails of the curves.

 

[stoky]

Loud, to be sure, but maybe worth it, in a Schuff's Garand.

 

[Gtscotty]

And how is the supressor going to like the additional muzzle blast of the higher powder charge?

Good question, I'm sure it will be louder than it would be on a 24" gun, but I'm willing to make a reasonable trade-off on that... 25" barrel equivalent is enough, 31" is too much. Liberty rates the Sovereign for 14" barrels in non-magnums, but says that short barrel applications will wear the baffles faster. I have an email in to them asking how much of an increase in baffle erosion they would expect with an 18" .30-06. Given that erosion rate must be tied to residual pressure at the muzzle, I'd expect the difference between 22" and 18" to be much less than from 18" to 14".

 

[Llama Bob]

And how is the supressor going to like the additional muzzle blast of the higher powder charge?

That's a question worth asking your suppressor manufacturer. They sometimes have minimum barrel lengths for certain calibers. I can't imagine 18" .30-06 being a problem since 16" .308 is so common, but it's worth an inquiry.

 

[.308 Norma]

Both .30-06 and .308 have nearly identical falloff per inch of barrel length. The ballistic advantage of .30-06 is very small (50-150 ft/s) comparing best loads to best loads, but that advantage stays basically unchanged as you shorten the barrel.

Years ago I used to hunt deer and elk with a buddy who used a Remington 7600 carbine. I was using a Ruger 77, .308 with a 22" barrel back then. Neither of us had a chronograph, but I always figured we were both shooting 180 grain Remington CoreLokts at about the same speed, and we both did equally well when it came to deer and elk hunting. My buddy's rifle just made a lot more noise when it went off.

 

[MCMXI]

The powder in either case is burned before the first few inches of bullet travel.

Liberty rates the Sovereign for 14" barrels in non-magnums, but says that short barrel applications will wear the baffles faster. I have an email in to them asking how much of an increase in baffle erosion they would expect with an 18" .30-06. Given that erosion rate must be tied to residual pressure at the muzzle, I'd expect the difference between 22" and 18" to be much less than from 18" to 14".

If you run a .30-06 Srpg load through QuickLOAD using 58.7gr of Reloder 19 and the 180gr AccuBond from Nosler, and choose a 24" barrel and 18" barrel, the velocity difference is 193 fps with the velocity from the 24" barrel at 2,819 fps. According to QL the 24" barrel burns 97.0% of the powder with a muzzle pressure of 9,731 psi. The 18" barrel burns 94.5% of the powder with a muzzle pressure of 13,515 psi. I've read many conflicting theories as to whether or not all of the powder is burned in the barrel in every situation but QuickLOAD doesn't seem to have any doubts at all. Just a guess but I would think that Liberty is concerned about erosion due to unburned powder moving at very high velocity, much faster than the bullet at the muzzle. I'm no chemist but my understanding is that as the pressue dops off rapidly within the first two or three inches of the barrel (due to the expansion of the combustion chamber), the conditions that are ideal for burning all of the powder such as pressure and heat drop off as well.

I'm not trying to make a point one way or the other but I find these types of discussion interesting. If you think about a 6" barrel on a revolver chambered in .44 Mag and a load consisting of 20.0gr of H110 behind a 220gr Barnes bullet, according to QL only 72.6% of the powder is burned in the barrel for a velocity of 1,329 fps. Now increase the barrel length to 20" for a velocity of 1,659 fps with 84.5% of the powder burned.

 

[entropy]

My overwhelming objection would be blast and noise. Those don't figure in your equation. So, lead on McDuff.

I have an 18" M49 Persian Mauser sporter in 8 x 57. It's an apples to oranges comparison, but there are some learnings. The velocity loss is not necessarily linear. The best loads in my M49 are only 100 fps behind my 23" VZ-24. Bore and throat tolerances may factor. The point is that I assumed faster powders would be "better" in the shorter barrel. Several people suggested that was not true, but I did not listen. After much testing I found that medium to slower powders that worked best in the 23" barrel also worked well in the 18" barrel, with one exception. You will have the further complication of a supressor.

I would counsel the following:. Try several tried and tested mainstream 30-06 loads in 4350 with 165 grs, whatever RL works best, Varget, and IMR 4064. I think you'll be surprised by good old 4064, but I'm speculating. You may also find you get better relative velocity from heavier for caliber bullets, so I would do the same with 180 grs But I've no idea what impact a can will have...

Sounds like a cool project.

I loaded 43.0 gr. of IMR3031 under 165 gr. Ballistic Tips and Partitions and got tight groups at 100 yards with my 18.5" 742 Carbine. It would be fine out of a surpressed 18" bolt. IMR 4064 is a good choice, too.

 

[browningguy]

I hunt with an HK SLB2000k with an 18" barrel and a Sako AIII full stocked carbine with a 19.5" barrel, both are accurate enough and seem to kill deer just as dead as a longer barrel gun. To be honest though my hunting is usually between 100 - 250 yards. I don't find the muzzle blast to be objectionable, but even when hunting I do wear electronic muffs.