Load Development ES & SD

[Belton45]

So my New Year’s resolution is to be more detailed and observant with reloading data.

Been working up loads on a new 308 to figure out how I want to save everything. Wile going through my chrono data the ES & SD numbers seem high to me. Granted these are 5 shots per load. I guess my lowest was a ES 22.3/SD8.6. Highest was ES53.5/SD21.2.

Should I be concerned with load where the ES is kind of high? This is brand new Lapua brass and all charges were exact with my FX120i scale. Necks turned to .014”. Using what’s left of my 8208XBR to see if I could find a good load 155SMK.

 

[K22]

Have you found a load that yields the group (dispersion of shots on target) that you need for your shooting discipline?

 

[Rocketvapor]

Sort (by weight) enough primers to shoot a couple groups.
Won't show on target for the first few hundred yards.

 

[chkunz]

You may find it helpful to also to calculate mean radius of your groups.

 

[Straightshooter1]

Sort (by weight) enough primers to shoot a couple groups.
Won't show on target for the first few hundred yards.

May not show up on target, but I do find it shows up some on the chrono data for SD's and ES's.

 

[Straightshooter1]

So my New Year’s resolution is to be more detailed and observant with reloading data.

Been working up loads on a new 308 to figure out how I want to save everything. Wile going through my chrono data the ES & SD numbers seem high to me. Granted these are 5 shots per load. I guess my lowest was a ES 22.3/SD8.6. Highest was ES53.5/SD21.2.

Should I be concerned with load where the ES is kind of high? This is brand new Lapua brass and all charges were exact with my FX120i scale. Necks turned to .014”. Using what’s left of my 8208XBR to see if I could find a good load 155SMK.

When I started reloading for my .308, my ES's and SD's were similar where very rare was I in the single digit SD's. I wasn't sure I could get my SD's to be consistently into the single digits, but I decided that was my goal and determined to find my way there, though I didn't expect to do as well as it has turned out. Likewise, I now use an FX-120i and also turn the necks. . . though turning the necks hasn't shown me to effect any of my chrono data. It's really a matter of finding the right powder, the load and primer for the bullet being used. IMHO.

For the 155 gr SMK, my best load was 45.0 - 45.2 grs Varget with Fed 210M primers, which got me SD's at 6.4 and ES's of 9 (but only for 5 shots). Typically these days, I get SD's from 4.5 to 6.5's with other powders and bullets, once I've found the right combination. . .and the brass prep procedure that works best for you.

BTW: I've not ever used 8208XBR, but it seems to me like a good powder for the .308. My go to powder these days is AR-Comp.

 

[Belton45]

When I started reloading for my .308, my ES's and SD's were similar where very rare was I in the single digit SD's. I wasn't sure I could get my SD's to be consistently into the single digits, but I decided that was my goal and determined to find my way there, though I didn't expect to do as well as it has turned out. Likewise, I now use an FX-120i and also turn the necks. . . though turning the necks hasn't shown me to effect any of my chrono data. It's really a matter of finding the right powder, the load and primer for the bullet being used. IMHO.

For the 155 gr SMK, my best load was 45.0 - 45.2 grs Varget with Fed 210M primers, which got me SD's at 6.4 and ES's of 9 (but only for 5 shots). Typically these days, I get SD's from 4.5 to 6.5's with other powders and bullets, once I've found the right combination. . .and the brass prep procedure that works best for you.

BTW: I've not ever used 8208XBR, but it seems to me like a good powder for the .308. My go to powder these days is AR-Comp.

That’s kind of the same path I’m on. Just want to see what I can do with ES & SD numbers. I have quite a bit of other likely powders, IMR4064, H4895, N140, Varget, RL15. Have not used the 8208 in probably 10 years and can’t even remember why I got it for lol. So figured I would start there to try and use it up. Just a Tikka/Proof/Supressor 20” 308 to play with.

 

[jackieschmidt]

You are waisting your time by performing any serious tuning with brand new unfired brass.

You need to fireform the cases in your chamber once, get your shoulder bump and sizing correct, and then work from there.

Also, as was mentioned by @K22, you need to decide what yardages you wish to shoot. Up to 300 yards, overall grouping ability will Trump SD & ES numbers. Out past that, velocity variations are more critical, hence you may have to compromise between great velocity variation numbers and good grouping capability.

In a perfect world, every rifle woul put five shots in a .200 or better five shot group with a ES of less than 10 and SD of less than 5.

 

[BoydAllen]

So my New Year’s resolution is to be more detailed and observant with reloading data.

Been working up loads on a new 308 to figure out how I want to save everything. Wile going through my chrono data the ES & SD numbers seem high to me. Granted these are 5 shots per load. I guess my lowest was a ES 22.3/SD8.6. Highest was ES53.5/SD21.2.

Should I be concerned with load where the ES is kind of high? This is brand new Lapua brass and all charges were exact with my FX120i scale. Necks turned to .014”. Using what’s left of my 8208XBR to see if I could find a good load 155SMK.

What distances do you normally shoot at?

 

[Belton45]

You are waisting your time by performing any serious tuning with brand new unfired brass.

You need to fireform the cases in your chamber once, get your shoulder bump and sizing correct, and then work from there.

That was my next step.. Was going to use some of my fireformed brass and go back and visit the mid to upper end loads that was shooting really good and see what differences I see.

 

[Belton45]

What distances do you normally shoot at?

Usually under 300yds but will be doing some informal 500yd matches at local club.

 

[Belton45]

This is more of a fact finding/learning mission. Just trying to get data and understand what I’m seeing. I have always found best group, and adjusted seating depth for that group and move on, which works great. Just trying something different with new 308.

 

[Mike Samer]

You should be able to get single digit SDs with that powder in a .308 for long strings. What velocities are you seeing? What case, primer and charge weight?

 

[Belton45]

You should be able to get single digit SDs with that powder in a .308 for long strings. What velocities are you seeing? What case, primer and charge weight?

Lapua LRP, 210M, went from 44-44.9 today. 2762 was with the 44.9 load.

 

[BoydAllen]

I had a friend who was under the impression that he could work up a very good load with the powder that gave the best velocity, with the bullet that he chose based on its BC. He nearly went mad trying all sorts of combinations. with those components. Finally, I suggested that he start reading a site that specialized in the caliber he was using, and after a while he had read favorable reports about a different powder, and bullet that others were reporting excellent accuracy with. The first time that he tried them, his groups were impressive. This taught him an important lesson, that you have to ask a rifle what it likes, not tell it what it is going to like. If a particular powder and bullet are going to give you what you want, they will usually do that right away, assuming some kind of logical load workup procedure, and if they do not, it is likely that they are not going to. Tell us about the details of your rifle, rest and so forth. I assume that you are looking for the best accuracy that you can get at the ranges that you shoot. If you can find excellent accuracy at a shorter distance, you can probably work on your loading details to improve the ES. I would forget about SD simply because your targets will not ignore outliers. They will reflect ES. I know that there is a lot on the internet about SD, but if you look into the sample size required to get a reliable number, I think that you will find that it is about 20, which is impractical for most of us if we are going to evaluate a number of combinations. What is your average five round group size at 100 yards with your best load? Are you shooting over flags.?

 

[Mike Samer]

Lapua LRP, 210M, went from 44-44.9 today. 2762 was with the 44.9 load.

You should be in a good range. I burned about 15 pounds of 8208 xbr in a 30 inch .298/.3075 Kreiger Palma barrel. 43.9 grains in a .308 SRP Lapua case was the sweet spot for it with Sierras 2156s and Berger hybrids. It peaked quickly for me, so back off at the first pressure signs. I shot that same charge year round which included some very hot weather.

 

[Belton45]

I had a friend who was under the impression that he could work up a very good load with the powder that gave the best velocity, with the bullet that he chose based on its BC. He nearly went mad trying all sorts of combinations. with those components. Finally, I suggested that he start reading a site that specialized in the caliber he was using, and after a while he had read favorable reports about a different powder, and bullet that others were reporting excellent accuracy with. The first time that he tried them, his groups were impressive. This taught him an important lesson, that you have to ask a rifle what it likes, not tell it what it is going to like. If a particular powder and bullet are going to give you what you want, they will usually do that right away, assuming some kind of logical load workup procedure, and if they do not, it is likely that they are not going to. Tell us about the details of your rifle, rest and so forth. I assume that you are looking for the best accuracy that you can get at the ranges that you shoot. If you can find excellent accuracy at a shorter distance, you can probably work on your loading details to improve the ES. I would forget about SD simply because your targets will not ignore outliers. They will reflect ES. I know that there is a lot on the internet about SD, but if you look into the sample size required to get a reliable number, I think that you will find that it is about 20, which is impractical for most of us if we are going to evaluate a number of combinations. What is your average five round group size at 100 yards with your best load? Are you shooting over flags.?

SEB Neo-X (although not a good bag rider yet for my non 3” guns) rear bag, and so forth. Gun is a thrown together Tikka with a prefit proof 20” 308, Zeiss S3 6-36, KRG Bravo chassis. Was not shooting over flags today, but I do own. Just a short range session for velocity reading shooting .5-.75 moa.

Oh and forgot to add a Thunder Beast Ultra 7 Supressor on the end of the barrel!

 

[Evlshnngns]

If neck tension is consistent, I would try a different primer.

There was a tale of an ftr shooter doing very well using only brand new 308 srp brass, then selling it as ounce fired. Internet loves a story.

 

[Chris kloster]

When you are in the node your velocity’s will show. This was the velocity recorded from my WSM yesterday

 

[Martin52]

Lapua LRP, 210M, went from 44-44.9 today. 2762 was with the 44.9 load.

Short barrel ? 2762 fps seems low using 44.9gr 8208 with a large primer.