OCW vs Ladder Test

Boomer686 said:
In this case I am running a 5.5-22 x 56mm Nightforce with NPR1 reticle. You can see most holes at that range with this scope but those few that you cannot you just drive up to the target etc.
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With that scope, I can see .308 to 300 meters no problems. For .223, I'm using a 8-32x56. It will work to 300 meters as long as there's not to much mirage.
 
Boomer686 said:
So I finally got stage one of load testing done this past weekend:Temp was 14C and test range was 215m with light but steady winds. Both loads measure 3.728 COAL

Load 1: 285gr Hornady Match BTHP: Best group node was produced with 85.5, 86 and 86.5grains H1000 measured 0.619" at 215M (this was the higher velocity node) with no signs of pressure even at max published load
Load 2 : 300gr Sierra SMK: Best group was 0.705 at 76, 76.5 7 77gr of H4831SC. Again no pressure signs even at max loads

With regards to the 285's I will run batches of five at each mentioned weight and measure those groups and go from there but will not chase it down too much further: as Litz implies says: you'd be better served practicing with your known decent load than forever striving to reduce your current MOA load if it is already accurate (below 1 moa). I am confident however that I can tweak the 300gr load further.

I am very please at how my rifle shoots the 285's and to be honest a little disappointed at the 300gr. I went into it thinking the 300SMK would outshoot the Hornady Match 285's: that being said I may even run a ladder test with 300SMK pushed by H1000 to further level the playing field with regards to the load development. The reason I did not do it this time is because I have only 4lbs of H1000 but a good supply of H4831SC.

Both current loads are still very promising though producing ~1/3 moa accuracy.

Thoughts?
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Great shooting but I would definitely want to retest the SMK's with H1000. The load density of the H4831SC load is lower vs the H1000 and that can affect LR tuning. Ideally, I want my powder charge to be right on the base of the bullet or just a hint compressed when running at desired pressures. That typically helps to keep vertical as low as possible.

But a tenth of an inch at 215m's is really very small and can be caused by wind or aiming error or follow through error or just the dispersion of your rifle.

as you had said, chase less... enjoy more.

If the results repeat, I would just start putting those slugs WAY out there. A 1/3 min boomer is something to treasure and really enjoy.

Jerry
 
I agree Jerry and I fully intend to do another ladder test with the 300's pushed by H1000. We had snow here today and -5C winchill. Hoping sunday is better so I can get this done and confirmed as well as a little more 285gr work so that I can confidently load a bunch over the winter.
 
If this is a new rifle, consider that the barrel will "break in" ... and when it reaches this state of "roughness", the tuning will change again. Likely needing the loads to be lowered to stay in tune. Once achieved, the tuning will stay stable until the bore enters its final phase of life.

Some will suggest the bore is "speeding up"... basically, the same thing and reducing the powder charge brings the harmonics back into tune.

If you haven't shoot a couple of hundred rds down this bore, I would hold back to make a big pile until this happens. Each barrel is different.. some break in in 50rds... some a few hundred.

This is not the shoot one, clean one that is part of getting the rough spots out of the throat... this is the bore actually getting burnished and forming its final surface texture... until it is burnt out.

Also, ambient temp and humidity may affect your load tune?????

I try and avoid making a large pile of ammo... as I hate having to pull bullets

YMMV

Jerry
 
Understood.

Barrel has ~300rnds thru it now. Temp on test day was 14C which is also why I am happy that it was not too near max load as next summer on warmer days I don't want to max the pressure threshold by being to close to max already in cold weather.

By a lot for this caliber I was thinking 200rnds. I usually shoot a few precision rifles in the same day so after a 50rnd volley with the .338lm coupled with whatever else I am shooting I am pretty much done for the day lol.
 
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