I have a recce-style AR that I built and it really prints good on paper so far at 100yds, I have not had the time or weather to shoot at farther ranges yet. My load is a 69 smk pushed by 25.5 grn varget in a win case and lit by a CCI br-4 primer. This load is nice on paper- so far 1/2-3/4", about 5/8" aves. Today I shot it over a chrono, just 5 rds (all I had left), and the ave was 2795fps. The es was 68 and the sd was 37, pretty shity at best. I imagine that this load would show all kinds of vertical at 500yds, max intended range of this rifle. The main question, how is the best way to une this load to get better numbers? OAL, powder charge, primers, or case. The cases are all trimmed to length and FH deburred, I have never had this much variation in fps with any other caliber using win brass. I use forster BR dies and weighted every powder charge and measured every loaded rds OAL. Tips or advice would be great.
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Re: How to tune a handload for good chrono numbers?
IME the SD & ES don't really determine groups size. Put it on the paper and see how it does. Sounds like you are doing everything beyond right so.....
IME the SD & ES don't really determine groups size. Put it on the paper and see how it does. Sounds like you are doing everything beyond right so.....
Re: How to tune a handload for good chrono numbers?
Only one way to find out... shoot it at 500. If you have vertical spread, then rework the load. Otherwise, if it ain't broke, don't fix it.
Only one way to find out... shoot it at 500. If you have vertical spread, then rework the load. Otherwise, if it ain't broke, don't fix it.
Re: How to tune a handload for good chrono numbers?
Varget is a poor choice and I much prefer 400's to the '4's.
I like Forster but prefer Reding TiN bushing FL sizers,for finite control. W/W 223 really doesn't make me too giddy,but by nature it is uniform enough to shade that ES/SD by a good bit.
Varget is a poor choice and I much prefer 400's to the '4's.
I like Forster but prefer Reding TiN bushing FL sizers,for finite control. W/W 223 really doesn't make me too giddy,but by nature it is uniform enough to shade that ES/SD by a good bit.
Re: How to tune a handload for good chrono numbers?
I shoot BL-C2 under 50 vmax in my 20 varmint AR with those primers and cases. Those loads have 6-7 fps SDs. I bought 16 lbs of varget last year when it was hard to come by and I had two 308 that loved it. Now both of those 308 are wearing 243 fast twist barrels and the only 308 I have likes 4895 alot better then varget. Basically I was trying to come up for a use with varget, I did sell one 8 lb jug. I have Varget, BL-C2, 4895, and 4831SC. I don't feel like buying another kind of powder. I am waiting on a new scope for this rig and for the weather to get better before I hit the longer ranges. Also the only long range I have is on my ground and it goes to 1200 yds, but I have been calling in yotes in that area and did not want to ruin that fun. I think it was simpler before I got a chrono, if the load shot good on paper and various ranges it was a keeper. Now if it looks good on paper at 100 I check the chrono and get bummed if the numbers suck before I even shoot at longer ranges. How much vertical can mid 30's sd cause?
I shoot BL-C2 under 50 vmax in my 20 varmint AR with those primers and cases. Those loads have 6-7 fps SDs. I bought 16 lbs of varget last year when it was hard to come by and I had two 308 that loved it. Now both of those 308 are wearing 243 fast twist barrels and the only 308 I have likes 4895 alot better then varget. Basically I was trying to come up for a use with varget, I did sell one 8 lb jug. I have Varget, BL-C2, 4895, and 4831SC. I don't feel like buying another kind of powder. I am waiting on a new scope for this rig and for the weather to get better before I hit the longer ranges. Also the only long range I have is on my ground and it goes to 1200 yds, but I have been calling in yotes in that area and did not want to ruin that fun. I think it was simpler before I got a chrono, if the load shot good on paper and various ranges it was a keeper. Now if it looks good on paper at 100 I check the chrono and get bummed if the numbers suck before I even shoot at longer ranges. How much vertical can mid 30's sd cause?
Re: How to tune a handload for good chrono numbers?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body">Only one way to find out... shoot it at 500. If you have vertical spread, then rework the load. Otherwise, if it ain't broke, don't fix it. </div></div>
I have to agree...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body">Only one way to find out... shoot it at 500. If you have vertical spread, then rework the load. Otherwise, if it ain't broke, don't fix it. </div></div>
I have to agree...
Re: How to tune a handload for good chrono numbers?
I wouldn't give up just yet until I chronied them again. I've seen to many variations in the same load because of conditions I was shooting in. I did a test just last week because I was able to get the range to myself. I was getting a SD at the muzzle around 26. I moved the chrony out to 100 against the target and 3" below the target and it had a SD between 6 & 7. When I moved it out to 175 and being more interested in not taking a chance on a flier I shot about 6" above the chrony and SD was in the teens. I've had the same load one day shoot in the teens and come back the very next day with the same load that was loaded at the same time and had single digits and vice versa. Only way I know to stop this is have IR's for the Chrony and I will one day if I find a job. If not I'll have to wait till the end of the year when I can get my IRA's out.
I wouldn't give up just yet until I chronied them again. I've seen to many variations in the same load because of conditions I was shooting in. I did a test just last week because I was able to get the range to myself. I was getting a SD at the muzzle around 26. I moved the chrony out to 100 against the target and 3" below the target and it had a SD between 6 & 7. When I moved it out to 175 and being more interested in not taking a chance on a flier I shot about 6" above the chrony and SD was in the teens. I've had the same load one day shoot in the teens and come back the very next day with the same load that was loaded at the same time and had single digits and vice versa. Only way I know to stop this is have IR's for the Chrony and I will one day if I find a job. If not I'll have to wait till the end of the year when I can get my IRA's out.
Re: How to tune a handload for good chrono numbers?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DH</div><div class="ubbcode-body">The main question, how is the best way to une this load to get better numbers? OAL, powder charge, primers, or case. The cases are all trimmed to length and FH deburred, I have never had this much variation in fps with any other caliber using win brass. I use forster BR dies and weighted every powder charge and measured every loaded rds OAL. </div></div>
A: Chamfer and debur the case neck after trimming to length
B: uniform the primer pocket and seat the primers 0.002 below the case base
C: measure the sholder positions of the cases and of the chamber. You want 0.002 longitudinal clearance
D: you are going to want a neck tension of 0.003 (semi-auto action)
E: take sized but unpowdered unprimed case and seat a bullet to normal magazine length. Better yet seat 5. Now manually cycle the bolt, slaming the cases into the chamber and popping then out in extraction. Now measure how much the bullets get set forward by the action. If this is greater than 0.003 you need more neck tension.
F: check/measure concentricity of sized cases (neck) and of finished rounds (neck and bullet)
G: measure OAL and base to ogive of finished rounds: compare with ogive position in chamber
H: You indicate you measure each charge--but fail to specify what tollerance you use, or whether you trickle up to a certain tollerance.
I: you stated 25.5 gr Varget; where did this number come from and how did you decide this was the magic charge weight? Perhaps you could google "Optimal Charge Weight".
J: after OCWing the charge weight, run bullet depth seating experiments to determin optimal bullet seat length.
That should about tun this load to that rifle.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DH</div><div class="ubbcode-body">The main question, how is the best way to une this load to get better numbers? OAL, powder charge, primers, or case. The cases are all trimmed to length and FH deburred, I have never had this much variation in fps with any other caliber using win brass. I use forster BR dies and weighted every powder charge and measured every loaded rds OAL. </div></div>
A: Chamfer and debur the case neck after trimming to length
B: uniform the primer pocket and seat the primers 0.002 below the case base
C: measure the sholder positions of the cases and of the chamber. You want 0.002 longitudinal clearance
D: you are going to want a neck tension of 0.003 (semi-auto action)
E: take sized but unpowdered unprimed case and seat a bullet to normal magazine length. Better yet seat 5. Now manually cycle the bolt, slaming the cases into the chamber and popping then out in extraction. Now measure how much the bullets get set forward by the action. If this is greater than 0.003 you need more neck tension.
F: check/measure concentricity of sized cases (neck) and of finished rounds (neck and bullet)
G: measure OAL and base to ogive of finished rounds: compare with ogive position in chamber
H: You indicate you measure each charge--but fail to specify what tollerance you use, or whether you trickle up to a certain tollerance.
I: you stated 25.5 gr Varget; where did this number come from and how did you decide this was the magic charge weight? Perhaps you could google "Optimal Charge Weight".
J: after OCWing the charge weight, run bullet depth seating experiments to determin optimal bullet seat length.
That should about tun this load to that rifle.
