barrel length and burn rate

[DJ Fergus]

In my case ,some old 3006 that have 65cm (nearly 26") barrel and 200gr Gamekink have max velocity with n560 (cant remeber what velocity).
Then we chop barrel to 50cm or (little bit under 20") and still have more velocity than the faster powder.

What I dont know is what happen if we put 150gr or 130gr bullet on the same test with same powder.

Yeah, I think that if you are going to run slow powder in a short barrel, then your velocity results will tend to be more impressive with heavier bullets than lighter bullets.

 

[josip89]

Yeah, I think that if you are going to run slow powder in a short barrel, then your velocity results will tend to be more impressive with heavier bullets than lighter bullets.

I am thinking same.
Slow powder and heavier bullets is the right combo.
What is best combo for lighter bullet I dont know?
But maybe somebody have similiar test with lighter bulle.

 

[Will Gray]

Heavy bullets: high sectional density do best in long barrels with slow burning powder. That is why military guns have LONG barrels. The Navy's old 5" 38caliber (38 times the bore diameter) is nowhere near the gun that the 5" 54 is. The Iowa Class battleships sported 16" 50cal rifles. If you are going to shoot heavy bullets (high sectional density) you will get the best performance from a long barrel and slow burning powder. If you are shooting lighter bullets, fast powder in a shorter barrel will be fine.

 

[josip89]

In longer barrel You would always have more velocity (with heavy or light bullet) than in shorter barrel.

I dont know what is best combo for lighter bullet in short barrel

 

[DJ Fergus]

In my 24" 25-06 with 80gr bullets , retumbo proved to be too slow. RL 17 was my next step faster powder that I had at that time. It worked out good but I believe something a little slower than RL 17 would possibly work better. Maybe RL23 or 26. I don't shoot that rifle much and don't want to invest anymore Time in it. RL26 is a highly versital slow burning powder. It would be one of the first powders I would tryout in a short barrel.

 

[TheDeicide]

Sorry I wasn't as clear as I should have been. A shorter barrel is better with faster powder and a longer barrel is better with a slower powder. I also picked up that the smaller caliber in the same barrel (30-06 vs 6.5-06) is the smaller bore builds pressure faster because it is more restricted so it would run a slower burn rate than the larger diameter bore. All other things being equal.

I'm trying to determine what length barrel to order and what powder. Most load data is for 24 and 26 inch barrels. If I better understand the correlation or a formula, I can save time and money. If I go from a 24" load data to a rig with a 30" barrel for example.

 

[Will Gray]

A 24" barrel was the standard we grew up with on our 22LR iron sight first guns. Those guns looked good and had enough sight radius to make them deadly accurate. True in revolvers as well: longer barrel better sight radius. Burning Bullseye or Unique, barrel length does not matter much. As magnum rifles came along, longer barrels became popular. The advent of rifle scopes made sight radius not an issue. Velocity and ease of handling are the competing issues. My 338 EDGE with a 30" bull barrel loves 300g Matchkings (90g of H1000). Same gun with a lighter 26" barrel really prefers 250g Gamekings. (100g of H1000). With 2" for a muzzle brake and you have a long gun in either case. It comes down to personal choice. Shooting from a small deer stand makes a long barrel a problem.

 

[cape cove]

I would say that the powders that produce the best velocity with a light bullet in a 26"barrel will also give you the highest velocity in a 20-22" barrel. At least that is what I've found over the years.

 

[josip89]

Logic is OK.
But what powder is that faster or slower.
And if You have some example?
I mean for lighter bullets.

 

[montana west]

Quote from P O Ackley:::: the longer the better.. all high powered rifles should be 24" and most magnums 26" for hunting.. now exceptions are the big cal like 416-458 the do well with 22" however my 416 taylor has a 24" but I am a tall big guy and a 22" in it would be fine.. the Ruger 416--I understand has a 23" and this is perfect. why the original winchesters M 70= 24" the remington 721 - 24" a good reason. and the Creedmore is a 300 savage case not impressive at all.

 

[montana west]

the longer the barrel the slower buring rate powders.....example in 25 " I use IMR 7828 24 " I use IMR 4831. same bullets same cal...

 

[cape cove]

Logic is OK.
But what powder is that faster or slower.
And if You have some example?
I mean for lighter bullets.

Well one example that I could give you is my 25/06's. I have one with a 27" barrel and one with a 22" barrel. With 87 gr bullets in my 27" barrel I get top velocity with the various 4350 powders and powders of this burn rate.. This is also true for me in my 22" barreled 25/06. In my 27" barrel I get top velocities with powders in the 7828 burn range with 120 gr bullets, and it holds the same in my 22" barreled 25/06. JME

 

[montana west]

cape cove you are right-- I forgot to mention this the heaver the bullet the slowers powders do work better.. the 25/06 is a great example you know it is a magnum.. In the old days we took the case dipped it into 4831 knifed off the top and put a 100 gr. bullet and she would kill the whitetails as far as you could see. and I am sure that 7828- h-1000 - and reloader25 will do better with the heaver bullet. . so you have two varibles bbl length and bullet weight.. I am close to Cranbrook BC.

 

[jellyjam]

A few years back I purchased a Remington Sendaro in 7mm ULTRA MAG my Dad and I bought a box of Remington premier ultra mag ammo with 140 gr core-lokt bullet fired 4 rounds over a chronograph and got avg velocity of 3424 fps. then I sent the gun off to have a 30" lilja barrel put on it. when we got it back we chronographed the same box of ammo,and it ran 3656 fps big cases need slow burning powders and long barrels.