how would you guys reduce your load Standard Deviation?

dthunter

dthunter

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My standard deviation is 21fps. 300Win Mag.
I ideally would like to get it down to 10 or less. Have any of you guys experienced a higher S.D. in a barrel that has fired 100 rounds between cleanings? I normally clean every 50 rounds or so. I havent tried primer changes yet.
Have any of you guys found seating depth to affect the s.d.? Thanks guys, I look forward to your ideas. Have fun, and Straight shoot'in!
 
21 is not that bad. Befor I clicked in here I was gona say try other primers and use a comparrator to check bullet seat depth. But it looks like you know this allready.

You can weigh your cases and bullets and separate them like so. Neck tension will also play a key roll.


Very good Q, I'm interested to see what other answers you get as well.
 
I have found more often than not...for me...it is the powder. Everytime my deviation creeps up a change of powder or less powder is in order. In theory seat depth could affect this but I would think only if it changes form round to round. As for being diry. Many rifles I have shoot better fouled but then shoot good clean also. To each his own on this one. Every gun likes different food.
 
If you dont load full trottle a trick that help is only to neck size but make sure before you reload them to see that they feed easy, discard the one that dont and since you dont go FT extraction will be fine on a good quality rifle the chamber will be thigt but perfectly round so only the one shot from it go back in it, not every rifle will perform with neck sizing you have to do your homework... JP
 
I'm a 270WSM shooter but an excellent combo which works also for 300 Win Mag is H4831SC powder and Federal 215 primers.
This combo is known to provide very muzzle velocity variation.
It's a favorite powder and primer in many long range load for a wide variety of cartridges.

Try some of Sierra's accuracy loads, they're normally 100fps below the maximum load.
I've had great luck with Sierra's accuracy load in 223 Rem, 243 Win, 270 WSM and 308 Win.

Alex
 
thanks guys for your input! Here is some more info. I am using federal 215Mag. Match primers, R22 powder. Winchester cases(wieght segregated,primer pockets uniformed, neck thickness uniformed,trimmed to a standard common length, flash holes uniformed). All cartridges are checked for concentricity (0.003" or less). Bullets are seated 0.060" off the rifling. Hope this extra info is helpful.
 
dthunter said:
thanks guys for your input! Here is some more info. I am using federal 215Mag. Match primers, R22 powder. Winchester cases(wieght segregated,primer pockets uniformed, neck thickness uniformed,trimmed to a standard common length, flash holes uniformed). All cartridges are checked for concentricity (0.003" or less). Bullets are seated 0.060" off the rifling. Hope this extra info is helpful.
Click to expand...

Well, I'd just use Sierra accuracy loads for 300 Win Mag. I only user Varget (for light bullets), H4831SC and Retumbo since they reknown for their being unsensitive to temperature variations and giving extremely stable velocities. Retumbo is a big favorite for 270WSM and 7Rem Mag but both Sierra and Lyman recommend H4831 for 300 Win Mag using heavy bullets.

One final thing, Federal Match ammo exists for 300 Win Mag and you might want to see how it performs. I always carry Federal 223 69gr and Federal 308 175gr Gold Match ammo in case I need to seriously test an unknown rifle which can't seem to shot well.
 
dthunter said:
thanks guys for your input! Here is some more info. I am using federal 215Mag. Match primers, R22 powder. Winchester cases(wieght segregated,primer pockets uniformed, neck thickness uniformed,trimmed to a standard common length, flash holes uniformed). All cartridges are checked for concentricity (0.003" or less). Bullets are seated 0.060" off the rifling. Hope this extra info is helpful.
Click to expand...

Very good prep work, the one thing I would ask is, how are you weighing your charge? and how full is the case?
I find to get an sd of 10 or less the cases have to be close to capacity (95% case capacity or higher) and the charges need to be checked to within 1/10 of a grain.


Annealing also will ensure that the case neck tension is similar case to case
 
dthunter

You may have better uniformity if you went to a standard large rifle primer. My 7mm and 300 mags have shot better with the standard primer. Reloader 22 is not that tough to ignite.
 
dthunter said:
thanks guys for your input! Here is some more info. I am using federal 215Mag. Match primers, R22 powder. Winchester cases(wieght segregated,primer pockets uniformed, neck thickness uniformed,trimmed to a standard common length, flash holes uniformed). All cartridges are checked for concentricity (0.003" or less). Bullets are seated 0.060" off the rifling. Hope this extra info is helpful.
Click to expand...

I've got a love/hate thing going with RL22 in the .300 Win. I get great close range groups, just to watch it start stringing shots vertically much past 400.

H1000 gives boringly consistent results at long range, but may not win the grasshopper group award at 100. Temperature insensitivity is a bonus.

I also notice that the .300 is generally happier at maximum loads.
 
dthunter said:
My standard deviation is 21fps. 300Win Mag.
I ideally would like to get it down to 10 or less. Have any of you guys experienced a higher S.D. in a barrel that has fired 100 rounds between cleanings? I normally clean every 50 rounds or so. I havent tried primer changes yet.
Have any of you guys found seating depth to affect the s.d.? Thanks guys, I look forward to your ideas. Have fun, and Straight shoot'in!
Click to expand...

Hi, after reading and thinking a bit
http://www.6mmbr.com/verticaltips.html
  1. Get in the habit of cleaning your barrel every 5-10 shots
  2. Use temperature insensitive powder such as H4831, H1000, Retumbo
 
Chrono's

I agree with AKD. 21 is is not bad. Chrono F-1 model is advertized as .5% accuracy. Assuming 3000 fps that is 15 fps built in error and not sure if that is shot to shot or average. Don't know what accuracy the three eyed chrono's have.What chrono you using.?
 
Hi guys, sorry for the delay in responding! My Load is getting 2933fps average for Berger210Gr.VLD"Hunting"(20Round sample) at 10-15Deg. Celcius. I only neck size my brass until they get very tight. Then I just bump them to fit good again. I have fired about 125 rounds since I last cleaned the rifle. I normally clean every 50 rounds or less, but the rifle is shooting so well, I am going to wait a while. I have a very regimented routine for cleaning that has worked well for my benchrest rifles.
My load density is close to 85% ish. I would like it higher(95-100%). The accuracy is too good to change at this moment.
By the way CHINBULLCO: Is that you Dale? Its good to hear from you. I met you last year at the gun show.(one of many people you meet! LOL!) I hope to try your bullets at1500+ some time. I will try the standard primer thing you suggested.
 
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