Load development made easy.

[SHRTSHTR]

Hi Michael,

I noticed on your 46.0 load your Extreme Velocity Spread was 20 fps. I realize it was only 3 shots and 2 were the same velocity and one was 20 fps higher.

As awesome as that group you shot was, how will that load work at lets say 1k (Vertical Spread)? I only ask this as I have been told that one would like to have ES in the single digits if possible.

This may be a dumb question but I am trying to learn.

Thanks,
Ray

 

[bigbuck]

Michael, I don't have the info on me at the moment for all my loads but the 85.5 grain load had an average muzzle velocity of 2943 .

bigbuck

 

[Michael Eichele]

Hi Michael,

I noticed on your 46.0 load your Extreme Velocity Spread was 20 fps. I realize it was only 3 shots and 2 were the same velocity and one was 20 fps higher.

As awesome as that group you shot was, how will that load work at lets say 1k (Vertical Spread)? I only ask this as I have been told that one would like to have ES in the single digits if possible.

This may be a dumb question but I am trying to learn.

Thanks,
Ray

20 FPS with this load would "theoretically" be 4-5" high or low for a 20 FPS extreme spread. Good harmonics also come into play here. While at 1K harmonics cant completely make up for the extreme spread, they do help quite a bit. It is common still to see 1/2 to 1 MOA groups at 1K even with more than 20 FPS spreads IF the harmonics are right. 20-25 FPS really is managable. Single digit ES's are nice but not always attained. One year I was working with Federal GMM ammo and found the ES to be nearly 60 FPS yet the ammo held 1 MOA out to 1K and much better at 700 and 800. The "theoretic" horizontal component was more than the groups were large. Then again, Federal GMM is a known "sweet spot" for the 308.

 

[Michael Eichele]

Michael, I don't have the info on me at the moment for all my loads but the 85.5 grain load had an average muzzle velocity of 2943 .

bigbuck

Have you loaded them up to 3200+ or have you stopped at 85.5?

 

[SHRTSHTR]

Thanks for the reply! It seems I have been a little to fussy

 

[Frogman77]

Hey michael,

just curious, do you do your load development the way you would shoot in the field? i.e. off a bipod or off a front rest, bag etc??

 

[Michael Eichele]

Hey michael,

just curious, do you do your load development the way you would shoot in the field? i.e. off a bipod or off a front rest, bag etc??

That is a big yes. I typically shoot of the bench with a bi-pod and a small sand bag under the stock. I also shoot in the prone position off of the pod with my back pack under the stock. I do not use mechnical rests and rabbit ears.

 

[Frogman77]

I'm guessing that the bipod will affect the overall rifle's "harmonics" so a load with it on will be different with it off??

do you put something under the pod off the bench like carpet to keep the muzzle from jumping/simulate softer ground??

 

[Michael Eichele]

I'm guessing that the bipod will affect the overall rifle's "harmonics" so a load with it on will be different with it off??

do you put something under the pod off the bench like carpet to keep the muzzle from jumping/simulate softer ground??

Couldnt answer the first question. As for the second, NO.

 

[AJ Peacock]

Couldnt answer the first question. As for the second, NO.

I have found a bit of vertical stringing on a couple of my rifles when shooting off a hard bench with a bipod (8lb 7mm Rem Mag and 9lb 338 Edge in original Savage tupperware stock). I was able to eliminate that stringing by putting a couple thicknesses of carpet on the bench. This is MUCH more pronounced with super lightweight magnum rifles. I don't notice it as much with my heavy rifles (18lb 338 Allen Mag, and 13lb 338 Edge with Joel Russo stock), but put the carpet down anyway.

AJ

 

[Topshot]

I notice that as the velocity increases the groups center move from the left of the aiming mark to the right of the aiming mark.
Is this a common phenomenon for a right hand twist barrel?

Wonder what causes this? Barrel torque resulting in a change in "Yaw of repose"?

 

[baldhunter]

Michael,thanks for posting this.I been working on loads for six rifles,with two different powders and several different bullets this year.I was using the ladder method too and now have my rifles shooting nice little clover groups.I too noticed the left,right movement when working up my loads,especially when I was testing loads with two different powders or two different bullets with the same load.I think there really is a magic "sweet spot"you just got to find it.A friend of mine has a Sako rifle in a 7mag,he's been trying to work up a load for it,he just wasn't getting the group he was looking for.I had him try some of my sweet spot loads I had worked up for my Remington in the 7mag.Whala,he printed a nice,tight little clover just like my rifle prints with this load.I'm passing your post on to him.
Thanks