These may be a rudimentary questions, but does anyone have any input on what an acceptable variance in bullet weight per given powder charge would be and secondly what are your thoughts on sealing case mouths and primer pockets. I have been reloading for about 3 years with the primary focus of making ammo that is affordable, functions, and is reasonably accurate for fun and practice
(if those two are not one in the same). I am now to a point where I would like to attempt to make a batch of ammo as accurately as I possibly can. I have a supply of military pulldown components and I have notice a about a 1.5 grain(plus or minus) variance in weight. Should I attempt to seperate these by weight and load them in lots or is this acceptable variance? I am loading 147 gr FMJ in LC 7.62 NATO cases with WC846 and also to a limited degree IMR4895. I am measuring case length and trimming along with chamfering the case. I am shooting these through 2 M1as, one with a "match chamber" and one with a standard GI chamber. Is there any particular reference manual I should be reading rather than asking stupid questions here and wasting everyones time? Thanks for any help.
Not a dumb question, and one easily answered.
For Bench Rest competition, I recommend weighing to .1 grain. For what you need, I think lotting them out to groups, based on .5 grain should suffice. I would get some 150 or 168 Sierra Match King bullets and try them in the match rifle to see which it prefers and use those for work requiring better accuracy.
There isn't really a good place to send anyone for this kind of question.
Agree with everything that Nickle has answered. I also
weigh each charge to 1/10 of a gr. Cases separated by
mfg and date. Some even weigh the cases, I do not. Do
check case length. Uniform, they all crimp the same pres-
sure. I'm not sure if the above makes a difference that
is measureable, but I do it. A bad shot when everything is
uniform pretty well indicates it's on me and not the equipment.
;D
Quote from: Oohrah on June 20, 2007, 03:00:47 PM
Agree with everything that Nickle has answered. I also
weigh each charge to 1/10 of a gr. Cases separated by
mfg and date. Some even weigh the cases, I do not. Do
check case length. Uniform, they all crimp the same pres-
sure. I'm not sure if the above makes a difference that
is measureable, but I do it. A bad shot when everything is
uniform pretty well indicates it's on me and not the equipment.
;D
I don't weigh my powder. I do use a really good measure that I trust, and it has been reworked. It's an RCBS with a Seeley Masker conversion and a baffle. Seeley is dead and gone, but even the stock RCBS measure with a baffle will work well enough to shoot some SMALL groups.
As Oohrah said, pay close attention to case length. This is far more critical than most folks think.
Thanks for the great info. I have used 168 Sierra HP MK with some surplus "match" brass I found at a gunshow. I was loading them with IMR4895 that I hand measured each load in a single stage RCBS press. I shot some 2 weeks ago and the best 200 yard group I could get was about 5 1/2 inches in a SA inc M1A "loaded" with a burris scope and an A.R.M.S. mount from prone position. My standard M1A I load with a dillon and I measure every 3rd round for powder constistency and I usually will get 4 MOA or a little better using once fired LC and pulled 147gr M80 projos. I was hoping for better performance but I guess that will do in a pinch. I know some of it may be operator error but at 25M I can shoot the center out of a 1 inch black square so I don't think it is my all my fault. I have an AR15 that will shot 1 1/2 inches a that 200 yard distance with cruddy IMI surplus. That is why I thought I might be doing something wrong with the load or maybe I am expecting too much out of that rifle. Thanks again.
Quote from: ukpharmd2003 on June 20, 2007, 10:36:10 PM
Thanks for the great info. I have used 168 Sierra HP MK with some surplus "match" brass I found at a gunshow. I was loading them with IMR4895 that I hand measured each load in a single stage RCBS press. I shot some 2 weeks ago and the best 200 yard group I could get was about 5 1/2 inches in a SA inc M1A "loaded" with a burris scope and an A.R.M.S. mount from prone position. My standard M1A I load with a dillon and I measure every 3rd round for powder constistency and I usually will get 4 MOA or a little better using once fired LC and pulled 147gr M80 projos. I was hoping for better performance but I guess that will do in a pinch. I know some of it may be operator error but at 25M I can shoot the center out of a 1 inch black square so I don't think it is my all my fault. I have an AR15 that will shot 1 1/2 inches a that 200 yard distance with cruddy IMI surplus. That is why I thought I might be doing something wrong with the load or maybe I am expecting too much out of that rifle. Thanks again.
Your match load sounds like it needs tuning rather than being discarded.
You CAN'T load a match load for velocity, you have to load it for accuracy. Of course, you do have to maintain enough velocity for it to get where it needs to go and do what you want it to do.
Try working the powder up and down in 0.5 gr. increments until you find a better shooting load, then tune on that one in 0.1 gr. increments till you find the best. Also check the seating depth with your bullets, this can make a difference. You want then as seated out as you can get them, but they have to fit in the magazine and say out of the rifling.
You can also check different primers, sometimes they show almost no effect, other times they have a marked effect.
Buckshot
Boy you should really be getting better perfortmance with that load as long as you were consistent in your reloading. Stay away from a maximum load though. Better accuracy is usually at lower than max pressure. I think I'd be looking at the scope and mount for issues, especially to see if the mount is tweaking the scope or the rifle mounting is stressed. Especially as things heat up. Also if the ejected brass is hitting your scope.This can jar the reticle and open up your groups.
Quote from: Nickle on June 20, 2007, 09:15:26 AM
For Bench Rest competition, I recommend weighing to .1 grain. For what you need, I think lotting them out to groups, based on .5 grain should suffice. I would get some 150 or 168 Sierra Match King bullets and try them in the match rifle to see which it prefers and use those for work requiring better accuracy.
Sorry, MIGHTY MOUSE, I took my own advice, did some more reading in this section, and just found this thread.
I'm sure by now if you took Nickle's advice and tried the Sierra Match Kings, you found that they have very little (if any) weight variance which is one of the reasons they are used by so many match winners.
You may want to check your twist rate. If you have the typical 1/12 twist for the 7.62, you may find that bullets toward the lighter end of the spectrum perform better. Some match rifles are equipped with a 1/10 tube, and are better suited for the heavier pills. You may also wish to try some IMR4064. I found it to be very consistent and wonderfully accurate in the .30-06 with the 168MKs.