another OCW test...

[LongRange]

i had a big detailed post going and my internet died so im going to make this one simple!!!

this is my BA110 260
28" shilen select match tactical chamber .263" freebore...479 rounds shot as of today
Murphy precision 20MOA base
night force 6 hole rings
night force ATACR
rifle basix SAV2 set at 10oz

started with a clean barrel...lapua brass fully prep'd..CCI BR-2 primers...142g SMKs seated .020 off....004" neck tension...RL-25 powder...i set my max charge at 48.2g because 48.5gs was over flowing my brass...48.2gs is about 3/4s of the way up the neck so its a nice compressed load IN MY RIFLE as i have a LOT of free bore!!
as youll see with a clean barrel my shots were pulling high left so i may have to re-shoot the OCW but ill see tomorrow morning as ill shoot the best load at 500yds when i finish my other OCW test with the 30" criterion barrel and the RL-19...

at start of test it was 104degs ammo was keep in my truck and was 92degs...pics are after the 3 test rounds...

first round is the high left...youll see a pattern here...



this was the second round fired in the test and hit the target stand and splattered so i moved to another dot for the last two of this charge but you can see again this round is high left...



the next 2 of the 46.8g test...



first round of this group was the hole to the high left..second round was in the pink third round was in the same POI as round 1...



this is were the barrel fouled and settled down...so it took 8 rounds to settle in and shoot...



this was the last 4 rounds...i loaded a few extra at the lightest charge to make sure i was zeroed....






tomorrow ill load 6 rounds each at 47.7 and 48.2g and shoot them at 500yds to see what load shoots best but im leaning toward the 48.2g load as quick load is saying 2906FPS at 53,036PSI...ill shoot over my chrony and report back tomorrow.

[sixonetonoffun]

Question, I thought OCW went round robin to avoid things like barrel warming and fouling from skewing results?

Just trying to follow what your doing there.

[LongRange]

Question, I thought OCW went round robin to avoid things like barrel warming and fouling from skewing results?

Just trying to follow what your doing there.

you are correct....i fired my 3 sighters at other dots and got zeroed...cooled the barrel then fired 1 round from the lowest charge weight then cooled the barrel...then fired 1 round from the next charge weight at a different dot then cooled the barrel...and continued this until all 18 test rounds were fired cooling between every shot and shooting round robin...ive said in the past that i wasnt a fan of this method of load development but i never follow it to the "T"....now that i have ill admit i was wrong about the OCW method and could of saved a lot of time and money...if followed to the "T" and combined with quick load this is probable the fastest way to find a good load.

[LongRange]

this is 48.2gs of RL-25 in a lapua case....



this is a pic of the difference in the free bore....left is in my shilen barrel at .020 off the lands....the right is in my criterion match barrel touching the lands...

[CharlieNC]

OCW and similar methods do not evaluate group size to select the charge, but determine based on identifying stable vertical poi.

[sixonetonoffun]

Not to go to far off topic but...

I find it of interest your using double base powder @100°F +- running near max loads without issue. That says something right there. Can't help but wonder if you would have to step to the next faster powder @40°F to achieve the same results? Or if the nodes are wide enough to be ok?

[LongRange]

OCW and similar methods do not evaluate group size to select the charge, but determine based on identifying stable vertical poi.

I understand how the ocw method works and how to select the best charge and then fine tune with seating depth.

I'm testing the 48.2g load because of the small group but am also testing the groups that shot the same.

[LongRange]

Not to go to far off topic but...

I find it of interest your using double base powder @100°F +- running near max loads without issue. That says something right there. Can't help but wonder if you would have to step to the next faster powder @40°F to achieve the same results? Or if the nodes are wide enough to be ok?

I'm not sure but will find out when it starting cooling off here.

As far as max loads with the RL-25 I'm not sure what it would be I just ran the numbers on quick load and chose 48.5gs as max but can't get that much in a case so I stepped down to 48.2gs...I'm out now and will post a pic of a 48.2g case in a few.

[LongRange]

this is a fired case from the 48.2g load...i know the primer is cratered from the pin i need to adjust the pin protrusion a little...



the wind was blowing again this morning about 25mph and from every which way and the only reason i shot 15 rounds this morning is because it was the last 15 cases out of 92 that need to be annealed and tumbled....the first 3 rounds the wind died off to about 5mph then picked back up full bore on the last 2...or it may have been the redbull and the monster i drank and i pulled them LOL...but i think this is going to be a good load with a little tuning and if the wind ever stops blowing this year ill find out...



im liking the RL-25 in this rifle enough that im headed to scheels right now to pick up 9lbs of it!!

[CharlieNC]

That vertical spread sure does not look like you are on a decent node to me.

[LongRange]

That vertical spread sure does not look like you are on a decent node to me.

agreed but ill re-shoot with no wind no redbulls or monsters to see....im thinking im going to end up somewhere between 46.8 and 48gs...like i said i only shot these 15 rounds because it was the last 15 and time to anneal.