Barrel length/velocity vs. powder


PDA






lencac
January 29, 2011, 11:58 AM
Hello boyz/galz
Top of the mornin:)
Ok, I have a question and I know the THR peeps can answer it.
I have 2 rifles and my intention is to use them for 1000 yrd. shoots.
One is a Steyr 300M Standard CISM chambered in 7.5x55 Swiss with a 22 in. barrel.
The second is a Gruning custom build on a Remmy 700 action, chambered in 30.06 with a 26 in. barrel.
For both I use 168 gr. Nosler or Sierra match bullets.
The Steyr load is 48gr. of Reloder 15. It generates 2650 fps MV.
The Gruning load is 56gr. of Reloder 19. It generates 2650 fps MV.
Both are with CCI BR primers
The load for the Steyr is ideal for that setup and requires nothing.
My goal is to be able to utilize the extra 4 in. of barrel length on the Gruning to generate 150 fps more MV. At 56gr. of Reloder 19 the case (Winchester) is getting pretty full. Going to max load of 57 gr. of Reloder 19 just about fills the case and generates only about 50 fps more MV.
So now my question: Should I go to a faster or slower burning powder? :scrutiny:

If you enjoyed reading about "Barrel length/velocity vs. powder" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
jerkface11
January 29, 2011, 12:04 PM
Bigger case with the same bore diameter = slower powder. Barrel length doesn't come into the equation.

rcmodel
January 29, 2011, 12:05 PM
Slower.

Whatever powder that gives the highest velocity in a long barrel will also give the highest velocity in a short barrel.

That almost always is going to be a case full, or even a compressed load of slower powder.

rc

brickeyee
January 29, 2011, 12:09 PM
The actual powder has finished everything within a few inches of bullet bore travel (some fast pistol powders are done before the base of the bullet clears the case).

After that the pressure just continues to fall as the bullet moves and the volume of the gasses expands.

A longer barrel gives more time for the expanding gasses to push the bullet, and unless you have a very small cartridge like a .22 RF longer gives more speed.


Have a look at QuickLoad.

USSR
January 29, 2011, 12:35 PM
lencac,

I cannot advise you on the 7.5x55, because I don't have one. But, I have shot the .30-06 extensively at 1,000 yards, and can give you the following advice: ditch the 168SMK's and RL19, and get 190SMK's and RL22. With somewhere between 60.5 and 61.0 grains you will reach 2900fps at a safe pressure level, and you will only need about 30MOA from your 100 yard zero to reach 1k. I would also highly recommend Lapua brass.

Don

ArchAngelCD
January 30, 2011, 01:30 AM
lencac,
I use a 168gr Sierra MatchKing bullet in the 30-06 and I can easily generate more velocity than you are now getting using a charge of 58.0gr H4350 or 57.0gr IMR4350. (just under 2800 fps if I remember correctly) Neither of those charges are the MAX recommended by Hodgdon. That charge of 58.0gr H4350 almost completely fills the case and delivered several sub 1/2MOA groups @100 yards from a Howa 1500 rifle. (one of the groups was only 1/4")

The problem is, according to several different burn rate charts H4350 is no slower than Reloader 19 but the answer to your question is a slower powder. Maybe you just need more powder because you are loading a charge of 56.0gr and Alliant says you can use a MAX charge of 61.0gr RL19 with a 168gr BTHP bullet in the 30-06. If you like RL19 up the charge until you achieve the velocity you're looking for while checking for high pressure signs.

lencac
January 30, 2011, 04:28 PM
Thanks guys:)
Me thinks this is what I'm going to do.
I'm going to use a slower powder (Reloder 22) and a bigger bullet (190gr. MK).
After running the ballistics charts I see that a 190 gr. @2650fps, due to it's higher BC will fly flatter, retain 200 ft/lb more energy and 110fps more impact velocity at 1000 yrds. while requiring 3.25 in. less elevation at 100 yrds. than the 168 gr. projectile @ 2650 fps. I believe that combo with the Gruning rifle will be able to easily generate the 2650 fps without having to really push the envelope very hard. No sense to overwork the barrel if not necessary.

lencac
January 30, 2011, 04:43 PM
I don't think I mentioned the format for the shoot. The club members are pretty close to approving the rules for this summer's 1000 yrd. shoot.
It's going to be an event that will test one's ability to, in real time, show a person's practical profficency. Timed event. To start everyone verifies their rifle is zero'ed @100 yrds. using center reticle. Then you get 7 minutes to take five shots to 1000 yrds. using standard 1000 yrds. competition targets with 10 pt. bullseye.
The shooter will need to make all his adjustments and corrections within that 7 minutes.
High score wins :what: Pretty cool uh?:cool:

USSR
January 30, 2011, 06:17 PM
lencac,

If you load 60.5gr of RL22 with the 190SMK (this load is in the Lyman 49th Ed. manual at 48,700 C.U.P.) and then dial in 31 MOA when you go to 1000 yards, you will be on the paper at 1000 yards - guaranteed, while the other guys are wondering where their bullets went and wondering what to do now .:D

Don

lencac
January 30, 2011, 09:18 PM
Thanks USSR. I'm starting at 55.0 gr. of Re 22. At 55.0 with the 190 gr. bullet seated at 3.325 in. (3.725 in. with Stoney Point) That puts the bullet just coming in contact with the lands. The throat on this barrel is .015 in. shorter than the 3.340 in. spec OAL will allow. The new Sierra manual lists the max load as 55.6 gr. of Reloder 22 producing 2700 fps. At 55.0 gr. with the 190 gr. the case (winchester) is completely full accounting for the bullet portion inside the case. I doubt 60.0 will all fit without a super compressed load if you could even get it to compress that much. Your spec of 31 MOA elevation at 100 yrds. to hit 1000 yrd. indicates the projectile is at 2800 fps.
I'm going to work around a 2650 fps. 190 gr. projectile. That will make for 35 in. elevation at 100 yrd to hit 1000 yrd. The scope's clicks are in inches. It's a Leuplold Mark 4 LR/T and each elevation click equals 1 inch. So 31 MOA is equal to 32.5 in. The difference between 2800 fps and 2650 fps is only 2.5 inches. And it will be a bit less wear on the barrel in so far as throat erosion goes.

USSR
January 30, 2011, 09:38 PM
Ya can lead a horse to water, but you can't make him drink.:rolleyes:

Don

ArchAngelCD
January 31, 2011, 02:50 AM
Hey USSR, don't you just love it when someone asks a question, you give them an answer and then they tell you you're wrong! :banghead:

USSR
January 31, 2011, 07:21 AM
Yeah, it's kind of hard to argue with Manuel Sierra. But I never saw Senor Manuel Sierra alongside of me on the 1,000 yard firing line.:D

Don

lencac
January 31, 2011, 08:14 AM
Yeah, and ballistics charts and my chronograph don't lie. Boom:p Pretty easy stuff. Thought it would be interesting question to post.
Oh, BTW ............. you do know what you find under a horse's tail ........... don't you?:eek:

lencac
January 31, 2011, 05:43 PM
Hey Arch, don't you love it when someone posts an answer that is their way or no way?
Actually USSR gave me the answer I wanted. I've handloaded for many, many years and I can see 60 gr. of RE22 will not fit in the case with a 190 gr bullet. With a 190 gr bullet I don't need to generate excessive MV. Besides it's just not necessary
Perhaps you like replacing barrels every 500 rds or so ... I don't :neener:

USSR
January 31, 2011, 09:46 PM
lencac,

You ask for help, someone tries to help you who has experience that you obviously don't have, and what is the saying "No good deed goes unpunished"? If you have handloaded for "many, many years", why didn't you know that the 168SMK bullet is not a suitable 1,000 yard bullet? And, I think you should do the handloading community a big favor, and call Lyman IMMEDIATELY and tell them to recall their 49th Edition Reloading Manual, as you have discovered an error in their load of 60.5 grains of RL22 at an OAL of 3.280", as it won't fit in the case. You do know that the .30-06's pressure specs is 50,000 CUP and 48,700 CUP is not excessive, and since the .30-06 is not an overbore cartridge, you are not going to burn out your barrel in 500 rounds? I have well over 500 rounds down my Krieger tube, and the throat is in fine condition. But, hey, you're not going to listen to anyone with experience anyways.

Don

lencac
February 1, 2011, 10:13 AM
oh blah, blah, blah......... I'm very impressed. Don't hurt yourself patting yourself on the back.:barf:
But thanks for the help. You're a swell guy :neener:

jerkface11
February 1, 2011, 10:35 AM
Why ask for help then? There are 2 people on this board who know about making .30-06 perform. USSR is one of them.

lencac
February 1, 2011, 04:57 PM
I did take his advise. I'm going to a 190 gr. projectile. Now it's up to the chrony to tell the tale. It leads me where it leads me. I've loaded 06 for a very long time to use at much shorter ranges. This 1000yrd thing is new to me. It isn't like unmasking the mysteries of the universe though.
If he wants a metal then he should just say so.
Besides I'm just mucking with you guys .................. y'all are too easy.
But I do apologize if I got anybody's panties in a bunch.
Shooting peeps are a little different breed though.

If you enjoyed reading about "Barrel length/velocity vs. powder" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!