Home Forums Hunting & Shooting Custom Rifles & Wildcats Been doing a little more experimenting.........

After owning an 18" .270Win I can tell you there are other benifits to a longer barrel other than FPS. I personally like the way a 22"-24" lightweight barrel balances.

Never was into the sub six pound rifle fad anyway.

Great info but wonder how some of the speed demons would react to the same treatment. Cartridges like the .257WBY or the .264WN, better or worse?

Terry

Terry Happy Birthday!

My thoughts exactly, on all points. My rifles all weigh 9-12lbs and have 25-18 inch barrels and I love 'em all. I have long wanted to do this experiemnt with those cartridges you mentioned as well as the STW, RUM and (Pick your caliber)/378 rounds. I suspect that the results would be different, but could not say for sure. Would sure be worth trying it out. If someone wants to fund such a project I would do the work.

TC1
I didnt test the two you mentioned, but the 300 RUM , I tested with H870 and H4895. Same results as a 308 or 223 or any others. In my opinion and testing, modern smokeless gunpowder burns like modern smokeless gunpowder. No amount of case shape, advertising, endorsements, etc, has any effect. Dont take that as the gospel, thats just what the chronograph and strain gages tell me.
Charlie

Charlie -- rather than posting the average velocity at each bbl length I think it would be interesting, and maybe more informative, if you posted the velocity for each shot at each bbl length.

Where the actual, individual velocities "clump" might be more informative.

Fascinating! I would have bet folding money that the 300RUM with H870 or other slow burning powders would have shown larger velocity gains with the long barrels than would have a more pedestrian cartridge using powders of moderate dosage and burn rates.

So, how does one determine now an optimum barrel length for a given cartridge and bullet? Surely we are not suggesting 16 inch barreled 257STW's. Not being a smart aleck, genuinely curious and want to think this through or perhaps begin creating a formla. Someting like with X size bore and Y size case capacity velocities are optimal and will not sufffer significant velocity loss vs (what to date has been the gold standard for uberfast rifles) 26 inches or longer, at Z length of tube.

How many times have we read, both ere and on the gun rags, "the 264 WinMAg with a 22 inch barrel is just a loud 270" Seems to not be so! Or "better hold out for a 257WBY with a 26 inch barrel, the 24 inch tube on the Vanguard and Remington will not allow the 'ol Roy to do what it was designed to do"

What to make of all this is the million dollar question.

Balance and blast count.

That said, whether an 18 or 28" bbl, if you put a good bullet thru vitals, the animal will never know.

No doubt I too like shorter than longer, but want a balance of the variables that get affected.

Charlie Sisk,
What a tremendous amount of work and foresight went into this experiment. We all owe you a lifetime of gratitude. All the gun writers in the world couldn't answer the question in 100 years better than you did. Thank you is inadequate, but THANK YOU!

+100

Now, give us an optimal barrel length formula!

Thanks Charlie, it's alway's been a theory of mine that 99% of the powder in a cartridge is consumed in the first 1" of the barrel anyway and the rest of the barrel is only a means for the pressure created in the first inch to react on the bullet. I've been taken to task for this several times but still think I'm right about it.


Terry

I Just came up with a brilliant idea! a 2 inch barreleld snubie revolver in 300 RUM! Titanium and scandium parts.... Wow, that would stop a bad guy in a hurry

I would suggest engraving your name, address, and spouses contact info on top of the barrel so when they dig it out of your head they know who to contact.

Good idea! See, when two great minds work together great plans come about.

I was joshin ya, of course. I mostly agree on the gunpowder gets all burnt up quicklike, but the gasses do expand for a while after. The big question is, for how long and at what pressures and gas speeds and for how far along the barrel.

Maybe the throat erosion of a well used rifle reveals the powder and gas burn??? Some worse than others. Seems like the barrels don't wear as much the further you get from the chamber, and it doesn't seem like the bullet speed changing would account for all the difference. Any thoughts?

I think that you are right on the money with that, and I have put forth that idea for a long time as well. Think about it, if it was bullet SPEED that wore out a barrel, then the MUZZLE end of it would be worn down the fastest! As it is, the predominant theory and logical one at that is that the throat erosion is caused form unburned and burning powder being blown down the tube like flaming and mega hot sandpaper particles. That, along with hot gases acting as a cutting torch. From about 2 inches or so on down, we have only expanding gases working on the base of the bullet and for the most part negligible wear all the way to the muzzle even though the bullet might be reaching 4000 fps out there. If someone ever solves the puzzle of barrel wear at the throat with high intensity cartridges a lot of financial success will come their way, I would guess. Maybe Roy Weatherby had it right with freeboring those high velocity rifles so as to 'pre wear' the most affectd areas and not lose rifling or have it go gunnybag since there weren't any there to begin with.

Here is another "thank you,Charlie" and good job
Could you see any obvious difference in noise/muzzle blast with the shorter lengths?
Eventhough we know we should wear ear protection hunting, a lot of us don't.
Huh? What did you say?

The 300 Rum with an 18 inch barrel has quite a blast. Didnt seem to make much difference using H4895 or H870. I was wearing ear plugs and muffs, not using a decibal meter.
Charlie

+1. Excellent info!

I have a spreadsheet that gives the optimum barrel time for any barrel, given length. The time is in mili-seconds, and you need a program like QuickLoad to translate that into FPS for any given load. Send me a PM and I will e-mail it to you, if you wish. Or, you can go to here: Linky to read more about it.
It is not an exact science, but it does cut down on load development time, and shots fired.

Thanks to Charlie Sisk for all of his work on the barrel length project. Very valuable information!

R.

Doesn't seem like 20 years ago...