04 June 2004, 17:06
CollinsVelocity Deviation in handloads?
Another "new guy" question.
I just put 30 rounds through the 300WSM Vanguard (my first non-military rifle (ouch)) and I was wondering what sort of velocity deviation I should be getting on reasonably built handloads (hornandy 150gr with 60gr IMR4350) 20fps, 30, 50?
Also, for Benchrest, is plus or minus 0.2 gr for powder OK? I'm also getting some variance in bullet weight. Normal? Should I sort these?
I guess I'm asking for your definition of "good enough".
One day I won't be the new guy, but I'll still be learning.
Collins
velocity variation can only be accurately determined with a chronograph. Such things as burn rate, load density, neck tension, etc will all play a role in the ES and SD.
Try to get below a 20fps ES, and for all but benchrest applications,..you will be more than satisfied. Try the slower powders compatable with that caliber/bullet combo to keep as much air space out of the load, use good dies, and take steps to make your case necks concentric (light turning or more) and the resulting consistency of neck tension will also help to keep that spread down. At least these are some of the things I do,..FWIW
If the bullets are varying by much more than .1-.3gr,.then I would sort them by weight.
.2gr of powder variance is beyond my range of acceptability. I shoot for no more than .1gr,..and most of the time,.I will take the time to get the loads exactly at the charge weight I want,..with NO variance. For out to say,..300yds or so,.that .2gr won't show up too much. Remember however,..that could be part of your velocity spread problem (inconsistent charge weights) Always calibrate the scale before loading,..and during loading to be certain of the charges.
05 June 2004, 14:12
dentonIf you're not worried about a 3 degree F change in the temperature of your ammo, or a 1 degree F change in the temperature of your barrel, then don't worry about a .1 grain difference in load in a 30-06 class cartridge. They all produce roughly the same change in muzzle velocity.
05 June 2004, 16:47
beemanbemea tenth of a grain of powder................????? I doubt that the scales we use are that accurate. I think that extrapolates to 3 or less little logs of 4350.
Hey, that can be the next anal driven obsession of reloading: Forget weighing charges or using a measure. Count the little grains of powder. In your valley time, you can seperate the little logs (or grains) into seperate piles of uniformity. Maybe even measure the little logs and load by cumulated measure, ie, "I get my best accuracy with 3 inches of 4350." Wow!
05 June 2004, 22:34
Cal SibleySome deviation is quite natural. None of our scales are 100% accurate. Bullets also vary a bit from one to another.
Temperature has a slight effect also. If you are new at this and taking your loads from a manual be careful to note the equipment used in determining the bullet speed. Generally the variance is about 50 fet per inch of barrel length. 26" and 28" barrels are common in testing, but you and I probably won't have barrels that long on our rifles so you have to make allowances for it. Also the powder you use will vary somewhat by lot. Some of these are not major items, but they will cause your velocities to vary somewhat. Best wishes.
Cal - Montreal
06 June 2004, 03:31
beemanbeme'Tis true. I use a Ohaus 10-10 that has been in the family longer than my kids................it behaves better too.

Collins, I have posted before: some folks reload to shoot and some folks shoot to reload. Makes no difference which one peels your banana, its a very interesting hobby. I wouldn't take Hot Core up on his offer if I was you. I sent him $100 (Confederate funds, of course) and he still hasn't assigned me a number. He's slower than the Montana Rifle Co.
