Heading to the range with a ladder!

[Cowsearshooter]

Lacking anything better than a 200 yd KD range, I'll be heading to Laguna Seca (Monterey, CA) to wring out the 30-06 with the 175 SMK and RL-17 loads.

The ladder starts at 53.5g and goes up to 57.5g by 0.5g for phase I.

So...should I be chronying the rounds at this point? I know, more information is better but it seems like I'll just be getting a safe load and a bracket for refinement.

Honestly, I hadn't planned to chrony anything (owing to the environment here lately) until I had settled on a powder charge.

Any advice?

 

[gcoulsey]

Re: Heading to the range with a ladder!

you've got it right, chrono numbers are nice, but not hugely important at this stage.

They would give you an idea if you had a particular target velocity you wanted to reach.. If your chargeweights are going up but your velocity stays about the same, chances are your at your max with that powder/bullet combo, and your just wasting the extra powder by flaming it out the muzzle.

Also, if 200yrd is your max range, an OCW test might serve you a bit better on your next test, 200yrds for a ladder test is a bit close..

Either way, good luck with your test!

 

[zuke]

Re: Heading to the range with a ladder!

I think it's more important to hit your target.
Don't worry yet about how fast your going,just get the hit's.

 

[Cowsearshooter]

Re: Heading to the range with a ladder!

I'll have to look into the OCW test. Seems I recall it being somewhat similar to the ladder test.

There's not a great deal of experimentation (with regard to cartridge efficiency) going on here. Truth be told, I am hoping that I might get away with pushing well above the listed max from Alliant powder (56.0g with the 168 HPBT).

I've capped the test at 1.5 grains above listed max for the time being. Even there, I'm only at 92% case capacity with Norma/Winchester cases.

Has anyone worked with this cartridge/bullet/powder combination at above max loads? Just curious, all normal disclaimers of liability apply.

Once the vertical stringing settles out, I'd hope for about 3000 fps in velocity. With IMR-4350, this barrel tended to favor the upper end of the above-max range (58.6 g IMR-4350 proved very nice).

In any case. I'll post some results as soon as I figure out the OCW test.

 

[Bob 964]

Re: Heading to the range with a ladder!

Because you are only shooting 1 round at each charge weight, there are too many factors (e.g., wind, barrel fouling, trigger pull, etc.) that could negatively influence (skew) the results of a ladder test. For this reason, I prefer to use Dan Newberry's Optimal Charge Weight (OCW) technique at a distance of 100 yards. This will factor out most of the wind effects, while providing data that I think is more easily interpreted.

Dan Newberry's OCW technique also uses incremental charge weights, but this technique uses 3-shot groups at each charge weight, and the shots are taken in a round-robin fashion until you've been through all targets 3 times each, leaving a 3-shot group on each target. This method spreads the error factor across all groups equally -- and you get 3 shots at each charge weight -- rather than the ladder test's one shot. So, if the barrel fouls or otherwise becomes inaccurate, the inaccuracies will be evident in all groups tested. This will give you more meaningful data than what you'll get from the ladder test.

 

[timelinex]

Re: Heading to the range with a ladder!

As others have mentioned. At close range like that your better off at 100yds doing an ocw. Combine that with a chrono and by choosing a load in the middle of a noad that also produces low velocity spreads, and that's how I have found my loads.

 

[Cowsearshooter]

Re: Heading to the range with a ladder!

I've got 2 rounds of each loaded and I still plan to do this all at 200--maybe some sort of hybrid process?

Here's what I'm thinking:
1. Ballpark zero scope with ball ammo at 50 yards--foul and warm the barrel (5 shots or so)
2. Confirm 200 yard zero with ball and batch test ball ammo (different issue) 25 rounds
3. Patch clean
4. Shoot ladder and spot the shots at 200
5. Clean and cool
6. Shoot ladder with confirmed safe loads at 200
7. Clean and determine node bracket
8. Load 3 rounds each between the brackets 0.2g apart (15 rounds)
9. Shoot OCW style round robin
10. Patch clean
11. Load 5 each of two best groups
12. Reshoot over the chrony and pick a winner
13. Go home and load 455 rounds of the winner
14. Practice, practice, practice
15. Win a match for once in my life

Any significant flaws in the process?

 

[Cowsearshooter]

Re: Heading to the range with a ladder!

Well, I got through steps 1-7 without a hitch. Back to the range tomorrow for 8-12.

Seems that this rifle prefers the upper end of everything, the node developed between 57.0g and 57.5. I plan to set the bracket at 56.9-57.7 and go in 0.2 g increments.

Oh, and for the record (in my gun anyway), FA Match 30-06 shoots really well, Korean PS 1975 30-06 shoots second best, and LC 68/HXP 1975 are a tie. Totally unrelated.

 

[leadbullet]

Re: Heading to the range with a ladder!

chrono the FA match load and duplicate its speed with your reloads, no need to do ladder test if you already found good ammo for your rifle.

 

[Cowsearshooter]

Re: Heading to the range with a ladder!

The trick there is finding the FA match bullet. By my recollection it's a 173gr FMJ--more or less what I've been working with with the SMK.

It's not a superlative load in that case anyhow, just the best of military production stuff I had on hand.

Heading to the range in 15 minutes...screw this NorCal weather!

 

[Cowsearshooter]

Re: Heading to the range with a ladder!

Well, weather did not permit anything more than getting the OCW drill done. Gratefully, the results were astounding!

56.9 grains and 57.3 grains each produced nearly identical groups. The others were not very impressive but these two loads turned in 0.74" groups at 200 yards.

I have not chrony'd the loads yet but I would expect that the heavier charge will be ever so slightly faster. Any reason to bother loading both or should I just go with the presumably faster load?

 

[timelinex]

Re: Heading to the range with a ladder!

Just something I noticed... I saw that you cleaned the rifle directly before started the ladder. You might want to do 1 or 2 fouler shots next time. POI definitely changes on a CLEAN, and especially oiled, barrel vs fouled.

 

[Cowsearshooter]

Re: Heading to the range with a ladder!

Good point. Actually, I ended up reserving 2 rounds each of Korean PS and Greek HXP ammo for just that purpose. Shot each ladder with 2 warming/fouling shots to start.