barrell length and velocity

[sludge]

This subject has probably been done to death already, barrel length v's velocity. First of all my go to gun for pig shooting in outback Australia is my 50 year old Winchester 30/30, open sights, 20 inch barrel. I've literally nailed hundreds and hundreds of wild pigs with this gun plus numerous Sambar Deer and a couple of unlucky Cape Buffalo, Unlucky I say for the Buffs as I was a bit under gunned. I've got a couple of Martini Henry's that are good pig busters too.
Now back to the subject - I have read a couple of older subjects on the forum relating to .357 in 16 and 20 barrels with a minimum gain in velocity around 50fps gain with the 20 incher. These posts from memory were from about 2007. Since then there quite a few other powders on the market in Australia ADI, (amongst a few others) I think this ADI Powder is available in the U.S.
What I am looking at is any statistics for velocity increase either .357 or 44 Magnum in a Rossi Puma 24 inch barrel over the 16 inch and 20 inch respectively, the Rossi 24 incher won't replace the 30/30 but either should be OK out to 100 yards or so.
Regards all !

[COSteve]

You have come to the right place with your question. First of all, I have both a Rossi .357 Mag 20" Carbine and a Rossi 24" rifle. I've had both since 2009 and shot thousands of rounds through each. They are hands down my favorite rifles to take to the range and also out 'woods walking' in the Rockies. The rifle has a tang rear and globe front sight while the carbine has a bolt top peep sight I added as a peep sight works much better with my older eyes than a blade type rear on the barrel.

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Now to your question. I started with shooting 2 bullet weights, 125 grn and 158 grn. I really like Zero JSP bullet in both weights as they are pretty accurate. In fact, I added the tang and globe sights to shoot at bowling pins at 200 yds with. With a 30" sight radius and a target aperture, a bowling pin at that range isn't that difficult to hit even though it has only about a 2" high portion where it's a bit over 2 MOA at that distance.

When I added the peep to the carbine, that extended it's sight radius to 20" and I can use that for bowling pins at 200 yds as well if I'm 'on' that day. I mention that to demonstrate that properly sighted, the Rossis are plenty accurate to shoot out to 200 yds.

Now to velocities. I started to use H-110 powder in the 158 grn bullets for max velocities. At 16.7 grns max charge I consistently got the following velocities over the 10 years I used H-110 for my high velocity 158 grn loads. I tested them on multiple outing at my range with my chrono and the following conditions: Elevation - 6,100 ft asl, Conditions - Sunny, Temperature - 84°, chrono - 15 ft from muzzle.

Carbine: Multiple 10 shot strings over the 10 yr period produced a consistent MV of 1,789 fps.
Rifle: Multiple 10 shot strings over the 10 yr period produced a consistent MV of 1,822 fps.

However, H-110 is famous for 2 things, first, you must fill the case within 3% of max with a strong crimp and second, it beats up the brass pretty bad with the 40,700 CUP peak pressure. I got tired of it beating up my brass so I looked around for another option. I read that Lil'Gun produced almost the same velocities as H-110 in pistols but with it's slower burning powder and larger charge produced much lower peak pressures; 25,800 CUP peak pressure!

I decided to try a pound and loaded up some test rounds with a max 18.0 grn load under my Zero 158 grn JSP and took them to the range. Turns out it was also 84°that day so the conditions were identical for the comparison. Same guns, same range, same weather, same chrono. I tried the carbine first and my results were so surprising that I ran a second string of 10 shots. I was expecting a slightly lower velocity out of Lil'Gun but that's not what I got.

Carbine: My 10 shot string produced a consistent MV of 1,952 fps! That's a 163 fps increase or 9.1% Increased velocity!
Rifle: My 10 shot string produced a consistent MV of 2,005 fps! That's a 183 fps increase or 10.0% Increased velocity!

It turns out that Lil'Gun really shines in a longer barrel than a pistol length. Best of all, the brass comes out looking in great shape and even after multiple reloadings it's still going strong. Needless to say, I've switched to Lil'Gun powder for all my 357 mag loads and because there is no restriction on downsizing the charge weight like with H-110, I use it on my medium power loads as well.

[sludge]

Thanks Steve, certainly impressive results, 2005 fps with 158gr is nothing to complain about, more than adequate for what I will want. Thanks again for your reply, regards

[COSteve]

Remember, your results may vary either up or down as I live at over 6,000 ft and Colorado is very dry so the air is less dense. That said, I posted that info on the old Rossi website before it went under and several other handloaders posted that they got similar results; one got even higher velocities but I suspect he fudged the max load a bit.

Also, if you are looking for super high velocities approaching 30-30 150grn speeds and don't want to handload, Buffalo Bore has their Heavy .357 Mag loads. They claim that out of an 18.5-inch Marlin 1894, their Heavy 158grn JHP loads reach 2,153 fps! They are able to use blends of powders as they have the equipment most handloaders don't and I'd love to see what those loads do in a 20" carbine and 24" rifle.

https://www.buffalobore.com/index.php?l ... tail&p=100

[marlinman93]

Personally I don't think the velocity gained by a longer barrel is as beneficial as the sighting radius gained by the extra length! Having an extra 4"-8" of extra barrel length with iron sights is a huge factor in more accurate shooting.

[COSteve]

Personally I don't think the velocity gained by a longer barrel is as beneficial as the sighting radius gained by the extra length! Having an extra 4"-8" of extra barrel length with iron sights is a huge factor in more accurate shooting.

That's why a tang sight on a rifle is so beneficial. The sight radius of the standard sighted 24" m92 rifle is 20" but the sight radius with the tang sight is 30", a 50% increase!.

Add to that the small aperture of a target peep sight which increases one's Depth of Field for a clear sight picture of both the front sight and the target (even at 300 yds) plus more accurate aiming system and the end performance difference is amazing.

In addition, adding a rear bolt peep sight to my carbine increased the sight radius from 15" to 22", a 47% increase plus the small peep sight also increases one's Depth of Field as above and the more accurate aiming system.

[horsesoldier03]

I have the Marlin 336 in 30-30 and the Marlin 1894 .44 mag with 20" barrels. My FIL has a Winchester Trapper with the 16" barrel. IMO, the shorter barrels tend to shoot higher, at least for me. I dont think 4" makes a gun anymore handy and honestly to me makes it feel awkward. I will stick to the 20" and the higher velocity even if it is only 200 fps or so.

[sludge]

Thanks all, MarlinMan my main reason for the 24" is the sighting radius, I'e tried a tang sight and a receiver peep sight and I find target acquisition slower for Boar on the run, some say a longer barrel slows you down but on a light levergun I have found this isn't so. I agree with COSteve re peep accuracy but I need speed and most pigs are being busted under 100 yards (some down to about 15 yards on occasion). I don't know what pig shooting is like in the States but it's nothing here in Australia to come across mobs of 20 to 30 several times a day depending where you are and how far you go on a quad bike.

[COSteve]

That peep sight on my 20" carbine is actually quick to acquire for me as it's right there next to your cheek. This summer I was shooting 8" steel plates at 100 yds with it and sometimes I'd see how fast I could follow-up. Works so well for me that I added one to my Mossberg 464 30-30. Now I've lengthened the sight radius on it and increased my sighting accuracy significantly too.

PXL_20201017_224822403.jpg

[marlinman93]

Thanks all, MarlinMan my main reason for the 24" is the sighting radius, I'e tried a tang sight and a receiver peep sight and I find target acquisition slower for Boar on the run, some say a longer barrel slows you down but on a light levergun I have found this isn't so. I agree with COSteve re peep accuracy but I need speed and most pigs are being busted under 100 yards (some down to about 15 yards on occasion). I don't know what pig shooting is like in the States but it's nothing here in Australia to come across mobs of 20 to 30 several times a day depending where you are and how far you go on a quad bike.

I would tend to think weight of the barrel, especially if it's longer, would be a big factor in how it swings. One reason many long barreled rifle were also heavier was for stiffness, so they didn't vibrate and held well. But in the scenario you described swinging a longer, heavier barrel at fast moving, multiple shots might prove to be a disadvantage having too much weight hanging out too far.

[mickbr]

I wish Costeve's posts on this subject could be posted all across the internet. Hear all too often the old "maximum velocity is reached in16"of barrel" schtick and the ballistics by the inch guys get quoted the most often. As mentioned slow burning magnum powders in pistol carts can create a benefit from the longer barrel, and this includes 44mag.

[KWK]

I've switched to Lil'Gun powder for all my 357 mag loads and because there is no restriction on downsizing the charge weight like with H-110, I use it on my medium power loads as well.

I, too, have seen the warnings about crimp and reduced loads with H-110, yet both it and Lil'Gun are used in 410 shotshells running at pressures around 10,000 psi. This is well below 38 Spl pressures, yet I see neither used in the 38, not even cast bullet loads. I haven't seen an explanation for why these two powders work at low pressures in one type of cartridge but not the other. Is it the shotshell primer, or some effect of the wad, or...

[COSteve]

I wish Costeve's posts on this subject could be posted all across the internet. Hear all too often the old "maximum velocity is reached in16"of barrel" schtick and the ballistics by the inch guys get quoted the most often. As mentioned slow burning magnum powders in pistol carts can create a benefit from the longer barrel, and this includes 44mag.

I think the issue with the 16" 'optimum' barrel length and the BBI information stems from the fact that most of the tests are done with commercial .357 Mag ammo. The issue I see with using that ammo is that it has been optimized for the short length of pistol barrels. Therefore, the burn characteristics of the charges are biased to burn fast and peak fast before the bullet leaves the short barrel.

H-110, W-296, Lil'Gun are all powders that were originally developed for use in long barreled shotguns and then adapted to use as 'magnum' powder in comparatively large cased pistol calibers such as the .357 Mag, 41 Mag, and 44 Mag. They don't fair very well at all in small cased calibers like 9mm or 40s&w as those have been sized small to fit in a magazine located in the grip and therefore have smaller charge weights that require very fast burning, high pressure powder characteristics to achieve the desired velocities.

So, it seems to me that commercially produced pistol ammo will 'run out of gas' in a longer barrel as opposed to using the slower burning, larger charges of 'magnum' shotgun powders in one's handloads. They produce a longer burn and produce much more gas to continue to accelerate the bullet in the longer barrel. This bodes well for a longer barreled levergun and every 'magnum' powder I've tried has a larger charge weight and produces better velocities well past the 16" 'optimum' length many talk about.

In fact, all of my testing since 2009, when I first got my pistol caliber leverguns, shows that there is a velocity benefit between a 20" and 24" barreled piece. I don't have a levergun with a barrel longer than 24" and the velocity increase between 20" and 24" with them isn't that large of a percentage increase so I'd not expect that a 30" barreled levergun would produce still higher velocities over a 24" one. In fact, I wouldn't be surprised if it were lower.

In addition, I have set aside some .357 Mag ammo 'warm' loads (near max charge weight) loaded with Unique powder, but not full power charges. As Unique is a pistol powder that was developed for use in the relatively larger cased calibers used in revolvers but is not considered a 'magnum' powder and not developed originally for shotguns, it will be interesting to do some chrono testing on different loads with that in my .357 Mag carbine and rifle length leverguns to see how it fares.

However, the average temperature won't get anywhere near 84° for about 6 months so I'm going to hold off on testing them to make it as much as an 'apples to apples' comparison as I can.