Myth! Short barrel velocity vs. std. 24" barrel velocit

[Big Squeeze]

There is a general consensus among many shooters out there that for every inch of barrel length lost, the loss in velocity is around 50 fps. I am somewhat curious as to how this myth or rumor got started.........For many compact rifle owners, including myself, this would be and still is, the main topic of discussion. For me, every time when I take my compact from its case, on a hunting trip or at the range, that subject of velocity loss, not that I mind, always comes into the conversation.........My actual chrony results for my 16.5" barrel 300 WSM contradict the 50 fps. per inch myth! I have also chrono`d three other compacts in 18" and 20" lengths in other calibers as well. Their results also contradict this myth!..........For comparison, several of my range buddies volunteered their 24" standard barreled bretheren in the same calibers as the compacts I tested..... Using the same identical reloads in bullet brands & weights, powders, primers, brass, COL, etc., I find that the average loss per inch is only between 15 to 25 fps...........The average % loss in velocity for the 16.5" vs. the 24" is 4.2%; the 18" is 3.6% while the 20" barrels only lose 2.75%. These results certainly blow this 50 fps. myth to pieces!................So! For all you shorter barreled compact rifle owners,,,, fear not!! You are very close in performance to the standard 24" barrel length while maintaing your accuracy as well............If not done already, this 50 fps. myth,,,, has been busted!!!!!!!!!

 

[longwinters]

I read an article on that very subject a while back. Seems like they said with certain barrels tested a shorter barrel, at times, shot a bit faster than the same barrel at a longer length. . . depending on the barrel. But I have not tested it with my chrony a/c I have a thing about cutting my barrels down inch by inch. :lol:

Long

 

[Big Squeeze]

Longwinters...............Don`t cut your barrels down just to see if it`s true! Nope! Dont do that! LOL!.....Since I bought my compact earlier this year, I have had three friends that have followed my lead with compacts of their own!............If one can accomplish the same thing, by using a rifle that is shorter, lighter, more manuverable and has quicker target acquisition, then why not have a compact!.......After owning a full sized 300 Win. for 35 years, my compact is a blessing and more fun too!

 

[TScottW99]

To blow it even more. I have seen a 20" Rock River AR-15 shoot 100FPS faster then a 24" Remington 700 :lol: Of course the Rock River AR's have a tighter chamber which helps alot.

I have always heard an average of 30fps per inch but even that doesn't always hold true. My deer gun is a 24" T/C Encore in .308 win. Since there is no bolt I have a shorter overall length yet maintain barrel length. Best of both worlds :wink:

 

[Guy Miner]

Big Squeeze - opposite here - the predictable results - my long barrel rifles shoot faster, considerably faster, than my short barrel rifles. Here's a couple of examples:

.45-70, 350 gr Hornady over 50 gr H4198

18.5" Marlin = 1946 fps
22" Marlin = 2120 fps

A difference of 174 fps, or 49.7 fps per inch. Now that was two different rifles, so chamber dimensions or other variables might have affected it somewhat.

Second example, a pair of .308's. Each with a Krieger barrel, each chambered by the same smith, with the same chamber reamer:

.308 Win, 155 gr Nosler competition over 46.5 gr Varget

24" = 2850 fps
30" = 2977 fps

A difference of only 127 fps, or 21 fps per inch. I believe the little .308 case isn't gaining much of a velocity advantage with a barrel in excess of 24 or 26", but when I'm shooting 1000 yards, I'll take every fps I can get!


:grin:

Heck, I also find it interesting that my 24" .308 Win actually produces higher velocity than my 21" .30-06, both of them shooting 165 grain bullets... I'm seeing 2800 fps with the .308, and only about 2750 fps with the '06, despite the much bigger case capacity of the old '06, so I'm left to believe it must be barrel length that's giving me the "free" velocity.

I don't think there's an iron clad rule about how much velocity change occurs for every inch of barrel. Your .300 WSM is a rather efficient case, with that short/fat design and I'd expect it to do well in a shorter barrel, but man, that 16.5" rascal has got to be something! :shock: I'll keep my .300 WSM at 24" thank you! :grin: Going to be a while before I get to test my .300 WSM, am waiting for my shoulder to recover from surgery, but I'd be happy to test it, and forward the velocity figures. Have long since been convinced, as you have, that there's more about barrel length choice than mere velocity figures. I don't much care for the blast of a short barrel, so I've generally kept mine a little on the long side.

You're getting what, about 100 - 200 fps less than the 24" barrel .300 WSM? That sounds about right.

Regards, Guy

 

[rick smith]

About 20-25 fps lost per inch of barrel removed. Different barrels with the same load will often give very different velocities. I shot two 30/06s over my chronograph last year one had a 20" barrel, the other a 22". The 20" barrel shot higher velocities with the same load. No hard and fast rules covering this area. I have seen identical rifles shooting the same load be 50fps apart. Just one of those good topics around a campfire.Rick.

 

[Big Squeeze]

Guy...................Your 45/70 results are very interesting! Same identical powder, charges, loads, brass, primers, everything etc? Apparently, there is a much better velocity advantage with a longer 45/70 barrel as opposed to a shorter one; a 49.7 fps. advantage per inch? Thats a big difference!....................Though on the flip side, your .308 is very much in line with the results I`m getting. A 21 fps. per inch difference between your 30" & the 24"........................How would you like to test my Ruger Frontier, 16.5" 300 WSM???? Hmmm? LOL! You`d probably have to go back for more shoulder surgery afterwards!!! Hope your shoulder recovers just fine!.........Make no mistake, my little Ruger Frontier does have some serious recoil!! But what fun! However, I do use my slip on Limbsaver recoil pad! That really cuts down on felt recoil by about 50%!..................My chrony results are as follows; the 150 gr. @3155 fps. (1.20" 3 shot group)................the 180gr. @ 2994 fps. (1.225" group). Both of those loads using IMR4350 are not quite at max. No pressure signs yet!...............The 200 gr. A/B came in @ 2828 fps. using 69 gr. of Rel #19 and is maximum! (1.150" group). That one is my elk load!............ The rifle weighs 7 lbs. 5 oz. w/scope.......Yeah! Based on my results, I`d say that the difference between my shorty and a 24" er is probably about 100 to 150 fps., or on average, about a 4% loss! That falls into between a 13 to 20 fps. per inch loss for me..........Not bad for a barrel, that is 31% shorter than a 24" while able to retain, 96% of the 24"ers velocity! I can`t complain!.........There isn`t as much muzzle flash as you would expect from a 16.5" er. Quite the contrary!........Your right though, there is no actual rule for velocity loss per inch in fps. Each rifle is its own individual. But for most cartridges, recognizing that some could go over and some under, if you could test them all with identical loads, I`d say that a 15 to 25 fps. difference per inch would probably be the average across the board.............Best of luck with that shoulder!........Try a Limbsaver!

 

[Guy Miner]

Yeah - I'm thinking about 20 - 25 fps is a more likely figure.

I was surprised at the results from the .45-70, but hey, they're two different guns, tested on different days. Same ammo - I loaded it all up, shot some with the short rifle, sold it. Bought the longer Marlin, took it to the range with the same ammo and was very impressed and surprised with the velocity increase.

Limbsaver is a great recoil pad! I always thought the one on my .25-06 was sort of silly and unnecessary, but now that my shoulder is a bit tender and weak - I think that .25-06 and the limbsaver will be the only centerfire rifle I dare shoot this season.

Regards, Guy

 

[bsmith]

Big Squeeze, thanks for the info. My 12 y/o likes his Ruger compact .243 more than my .25-06. I always thought he was losing velocity with that short barrel. Maybe it's not as bad as I think. :grin:

 

[Big Squeeze]

Bsmith............Does your 12 year old have the Ruger compact or the Frontier set up? The difference is that with the Frontier Mk2, you can mount a scope conventionally over the action or an EER scout scope on the barrel. I have the Frontier w/ 2 scopes that I can switch back and forth, scout or conventional.....Either way the barrel length is only 16.5".......To me, these Ruger compacts have to be one the best handling rifles that anyone could take into the field. Simply superb!

 

[bsmith]

Big Squeeze - the .243 is the compact model. Regular receiver-mounted scope. You're right about the handling. It swings and points great. He likes it because of his size and the short length of pull. It's an inch gun at 100 yds, minute-of-deer-lung anyway. It would be a nice spot and stalk gun but we don't have much of that here in Kentucky. It works well out of a tree stand though. I'm going to have to breakdown and get a chrono so I can test this thing and I need it for my other guns anyway...

 

[Big Squeeze]

Bsmith................There is a very interesting article that is an excellent read regarding the Ruger compacts! After I read it earlier this year, I became convinced to try the compact and convert from the full sized rifle.......... Fortunately last March, I was able to get my hands on one of the last 300 WSM`s in the U.S... Ruger, for legal & patent reasons, discontinued the WSM`s in their Frontier line........Perhaps you have read this before. If not, then I`m sure you will find it very interesting..............Go to.........www.shootingtimes.com......click on "long guns".........scroll down & click on pg. 2......Scroll down until you see the title "Short answer about scout styled rifles"......then click.....Within this 4 page article by Dick Metcalf, he talks about velocity loss or the lack of it with the shorter 16.5" barrel as compared to the 24." My chrony results are on par with his test rifle results. This will also apply to your son`s .243 compact. He also says that the shorter barrels are more accurate than the longer ones and explains why that is so!.......Please let me know what you thought of that article!...............Big Squeeze

 

[JD338]

I'm going to have to breakdown and get a chrono so I can test this thing and I need it for my other guns anyway...

One of the very best reloading investments you will make.

JD338

 

[bsmith]

JD338 - Since we've established that I need one, which one do I get?

Big Squeeze - I read the article. I was thinking that the shorted barrel should be stiffer and therefore more accurate. I don't have another .243 to test against but I'll concede the nothing is lacking on the compact. Around here everyone wants the 7MM, 270, and 06's. You can't even find a used .243.

If I was going on a stalking prairie hunt, it'd be a difficult choice on which rifle to take. Only 1 deer has been shot at, and taken, with that .243 and my son said it worked great. Our youth weekend is in 2 weeks and we're both ready to be out there. Once I have the chrono, I'll run some tests using a box of factory ammo and some handloads.

 

[Big Squeeze]

Bsmith.................I don`t see any reason why you couldn`t use the .243 for the prairie hunts! Use the heavier bullet! I would also go with a 200 yard zero. Preferably closer, but out to 300 yards, the .243 should do fine on deer with a well placed shot............One of these days, you just may want to follow your son`s lead in his liking of the compact and get one for yourself?? That little Ruger Frontier in the 7mm/08, is absolutely ideal for deer. People have also taken elk with that cartridge. In that same rifle, it is flatter shooting than the .308 Frontier.......Its dimensions may be designed better for smaller people or youth. But even in my case @ 6"3" 240 lbs., it can also be used by us bigger folk too with excellent results & satisfaction!...........Man o man! If you could only get your hands on a 300 wsm Frontier. Then you wouldn`t have to worry about keeping up with the 270`s, 7mm`s or the `06`s in your area!!!! You would more than likely exceed them all, and in a smaller & cuter package too! She is one helluva thumper!!!...........There may be some gun distributors out there that bought some of these after learning that Ruger was discontinuing them. They may have new ones laying around. If by chance I find a distributor that has one, I`ll let you know just in case you get the bug!.......After seeing my chrony results, my friend also wants one, then he`ll sell his `06...........

 

[Guest]

JD338 - Since we've established that I need one, which one do I get?

I'm not JD, but I can speak from experience of owning two different chronographs. I have a PACT Professional (which is a great chrono) but I won a Beta Master Chrony in a contest about a year and a half ago, and I have to tell you I love it. It is easy to set up, light enough and small enough to pack to the range in my regular shooting box, and it works just as well as the PACT. If I had never used the BMC, I'd be singing the praises of the PACT, as it does a wonderful job and is very consistent (although the printer on mine freaked out a while back, so I am going to have to send it in to PACT for repair). Either way, you're going to be pleased, but for the money ($120 or so from various online sources) the BMC is the way to go.

 

[bsmith]

Dubyam - I'm sold. I'll see if Cabelas in Mitchell has any next week. They're on sale at MidwayUSA too. I've watched 'em get whacked at the archery range. I hope I don't that myself. You just know that we're going to have to see how fast everything is - sling shots, arrows, bb guns... Do you have a favorite spreadsheet / software for tabulating results?

 

[Guest]

Actually, I built my own spreadsheet, but I am a numbers nut, and pretty handy with excel. If you understand statistics a little bit, you can draw up your own spreadsheet to work from. Pretty much record everything you can, including weather and such, and then as you get farther into it, you'll know what you can leave out, or what you really use, and work from there. Excel has functions that will do all your statistical calculations, and will even calculate the statistical significance of the difference between two means, if you want to go that far. Not many people do. It usually requires a terribly large sample size, which most folks don't want to shoot.

Also, as far as not shooting the chrony at the rifle range, get a laser boresighter and a white paper plate, and you can pretty much set things up where you won't have that problem.

 

[6ppcar]

I'm going to have to breakdown and get a chrono so I can test this thing and I need it for my other guns anyway...

One of the very best reloading investments you will make.

JD338

Chronographs are nice and i don't think i could get along without one, but they break a lot of peoples hearts when they see the real vel. that there pet rifle really produces.
A lot of good guns are sold because they did not give the speed their owners thought they should.

 

[FOTIS]

I had an Oehler 35p. Now JD338 owns it. I now use a Beta Master Chrony .