Sequence for accurizing ammo.

[dcamper]

I’m new to this thing, so please excuse my level of ignorance - the bar's been raised... .

I’m shooting a Savage 110 tactical in .308 at a hundred yd. range. Although it may not be the best situation, I’ve been doing an OCW type of test using 5 shot groups. Eventually I plan on stepping to a 200 yd. range to help validate my efforts.

I’ve tried Hornady 168 Amax, and Sierra 150 SBT. The best ‘consistent’ group size I could from these two was in the .8” range. That’s about what the factory federal SMK’s gave me too. I’m trying to let group size and the least POI shift between charge weights dictate the OCW.

Next, I switched to Sierra 165 SBT. A definite improvement, they seem to want to play better. 1st question; I had several .6 inch groups as I stepped through the .3 gr. increments, but the node point with the least POI shift between weights were .8” groups. Now, there was a gusting cross wind, and the main spread of the ‘node’ groups were in the horizontal plane, vertical was about .4. I’m thinking just further develop within the node point, speculating a non-windy day would tighten the groups up some?

To continue down this path, do I take the .3 gr. Charge weight(s) that’s in the node area and do the stepped CBTO/jump evaluation, or do I re-do the node area in .1 gr. increments for further refinement/group size reduction (which comes first)? Or do I even need to further reduce the charge weight increments?

In my mind I’m seeing this leading to consistently smaller groups. My plan would be to chronograph the ‘best load’ and use that fps to narrow the development window for the Sierra 165 HPBT and 168 SMK. Does this make sense?

 

[Feurhand]

Bumping for interest.

 

[1moaoff]

Look in the reloading section.... take a few nights and start reading threads...

Its all there already.

 

[dcamper]

I'm sure you're right, I'll throw a few more nights into it. thanks.

 

[Mike402]

Just a few comments to help you out and make your life easier. You don't need 5 shot groups, three is plenty. You should be letting barrel cool in between shots so if you do 5 shot groups x 6 charge weights, you'll needlessly burn components, and will take you quite a while to get through the process, and you'll start to tire and throw shots.

You don't need to do OCW at 200 either. 100 will tell you everything you need to know.

You also don't need to do .1 gr increments. If you find same point of impact with .3 gr difference, your load is right in the middle of that. I actually do .4gr increments because the node windows are usually larger than .3 grains, and I pick a nice even number in the middle. For example if I have same POI at 42.2 and 42.6, I'll go with 42.4.

Then proceed to seat depth. If you are magazine limited, load to longest OAL. If you have to room to play, start .015 or .020 off and go up or down by .04 and you'll find something that will work the best. You'll want at least 300 yards for that though.

Chronograph will come at the end, and yes you can use that velocity to narrow down for the other bullets.

Don't make it more complicated than it needs to be.

I’m new to this thing, so please excuse my level of ignorance - the bar's been raised... .

I’m shooting a Savage 110 tactical in .308 at a hundred yd. range. Although it may not be the best situation, I’ve been doing an OCW type of test using 5 shot groups. Eventually I plan on stepping to a 200 yd. range to help validate my efforts.

I’ve tried Hornady 168 Amax, and Sierra 150 SBT. The best ‘consistent’ group size I could from these two was in the .8” range. That’s about what the factory federal SMK’s gave me too. I’m trying to let group size and the least POI shift between charge weights dictate the OCW.

Next, I switched to Sierra 165 SBT. A definite improvement, they seem to want to play better. 1st question; I had several .6 inch groups as I stepped through the .3 gr. increments, but the node point with the least POI shift between weights were .8” groups. Now, there was a gusting cross wind, and the main spread of the ‘node’ groups were in the horizontal plane, vertical was about .4. I’m thinking just further develop within the node point, speculating a non-windy day would tighten the groups up some?

To continue down this path, do I take the .3 gr. Charge weight(s) that’s in the node area and do the stepped CBTO/jump evaluation, or do I re-do the node area in .1 gr. increments for further refinement/group size reduction (which comes first)? Or do I even need to further reduce the charge weight increments?

In my mind I’m seeing this leading to consistently smaller groups. My plan would be to chronograph the ‘best load’ and use that fps to narrow the development window for the Sierra 165 HPBT and 168 SMK. Does this make sense?

 

[dcamper]

Thanks for the feedback.

First; saying upfront I don’t need to be tired to throw a shot, I’ve proven the skills to do it anytime.

You’ve hit one of my root issues. The needlessly burning of components is a concern. With my primer & powder supplies dwindling and replacements seemingly nonexistent, I wanted to be as efficient as possible and didn’t know how. Because of my ignorance I feel like I wastefully chase my tail most the time.

I do have a charge weight node (43.1 – 43.4) that gave tight groups and only about a .120” shift in POI. That was the about least POI shift among the stepped loads. So: stop thinking I need to look at .1 gr steps, just load at 43.3, to do my stepped CBTO to attempt to tighten groups from there. My range only goes to 200 yd., hence my reference…. It’s what I’ll use for the jump test.

I do have a thermometer strip on the barrel and use that to allow the gun to cool if it hits 120f or between groups, whichever comes first. I also rotate between the .308 and .243 or 17HMR for my groups; sometimes I just need the others to validate the nut behind the trigger isn’t causing those damn blunderbuss patterns out of the .308….

 

[Buzzinga]

If you have a node and accuracy is 3/4moa, load and shoot it. After 50 or 100 rounds, you can always go back and tweak seating depth if you feel the need.

 

[dcamper]

You’re likely right Buzz, I was basing my hopes on my other Savages. Thanks for the reality check (damn parade poopers). I'll just have to accept it for what it is.

Here’s the reference that made my expectations: The .243 will give me a .3 about 20% of the time and .5s or less 80%... I probably didn’t have 300 rds invested to get there. I have a 75 gr rd., and a 87 gr rd. that almost always returns sub .5 even with my incompetencies in play, and a 100 gr spbt that shoots sub .7 MOA. I only shoot to 200 yd. The .243 federal GMM (what I use for a reference standard) gave me a little less than .8 too. My expectations for the 308 were in that family (+/- 10 %).

I was hoping to navigate to .5 or less fairly consistently. That’s been my goal. 600 rds later, and I ain't close.

Hell, the Savage 17HMR gives me mainly sub MOA & some .8s on a calm day (unless my range neighbor farts in my direction, then it goes to crap….). So, in relative terms the .308 has been frustrating and underwhelming.

 

[Buzzinga]

Sorry bro, I actually deleted that part of my post to make it more constructive, lol. If small groups are your goal, the .308 just isn't the best option. But, if it were me and I were trying to get my groups smaller I would take these steps:


1. Shoot from a solid rest, not a bipod.
2. Perform a seating depth test using three shot groups in .003" increments, move the bullet out of the case. 5 or 6 depths would probably work fine.
3. Use wind flags, even crappy DIY flags are better than nothing.

Good Luck, and don't let us parade poopers get you down,

 

[dcamper]

damn delete key. serious, thanks for all feedback.

Lesson learned with the Lapua. I switched from a brand I thought would be a ‘win’ (but I won’t name it) due to what I considered surprising variances in both length and weight: Even once fired cases were 1.983” to 2.013”. I culled the sub 2”, and then only kept the brass that was within a 14 gr weight spread, netting 86 out of 200. Expensive education…. Yea, so I now have 202 Lapuas; OAL +/- .001”, weights within 2 gr. Coinciding with this, I started using Sierra 165 SPBT’s. New brass yielded occasional .8s, and once fired gave three .6s out of (10) 5 shot groups during OCW test. It could have been more if I wasn’t so damned incompetent-That’s the jpg. The PDF breaks down the poi shift between weights for node info. 1st time adding files, hope it works.

Practicing off a bag/backpack is on the short list once I hone in my groups. In the field that's far more likely than a bench and bipod. To date I’ve used the stars and stripes that is flown at the range for angle of attack and a weather app on the phone. Should I get more granular?

This site has given me insight into a whole lot of variables that I didn’t even know existed that I can control. I used to leave the range hoarse from calling shots, not as much anymore.
I understand about delusional expectations with the gear I have. I sure don’t expect those amazing .1/.2 groups I see getting posted, nor do I see me shooting over 450 yd. Just driving for the smallest possible with the gun/ammo. Hopefully my income is on the back side of the bell curve compared to the rest on this site, so my gun and ammo expenditures have to be judiciously weighted and prepared for (damn it). I doubt if I’ve been able to send more than 1.5k rds down range in the last 6 months due to cost.

My foundation for the thought of a .308 being able to shoot tight groups came from a forum that talked about using Varget. Someone posted some pages from handloader magazine #257 that had some wonderful info to build off of. It inspired me. With my typical defective thinking, I also assumed the metallurgy, metrology, and machining capabilities of today could make even an old school round, & ‘poor man’s’ gun capable of shooting to higher standards. Here's that link.
http://www.opticstalk.com/best-varget-loads-for-308-win_topic16874_page1.html

 

[Buzzinga]

41.3 and tweak seating depth. You can see that both 41 and 41.6 have almost the exact same poi as 41.3 so that is a node. The next step is to adjust seating depth. I prefer small increases like .002" or .003". Load up maybe .015-.020" worth of movement (5-8 loads) and look for the smallest group.

 

[dcamper]

10-4; I'll likely go for .003 jumps - my normal uncertainty is +/- 001.