A Little OCW Help Please

[mike21]

Followed the directions for Optimal Charge Weight (OCW) as best I could. Wondering if anyone more familiar with this method can see a happy barrel or a charge weight worth investigating in the 100 yd targets below.


McGowen, 26”, 1 in 9” twist, in .243 cal.
Berger 95g, VLD Target
Hodgdon Superformance
Max charge selected was 44.4g (8% reduction, then two +2% sighters, then +.7% between charges came out to 7 charge weights = .3g between loads)
Used .040 Jump. I know it’s probably too much, but wanted to use one of the figures for the Berger recommended seating depth procedure later on (touch/jam, .040, .080, .120).
No chrono available, but no “visible” pressure signs.


Tried to place a red dot at about the center of each group. For reference, the black lines are 7/8" to the tip of each red diamond. If you see anything noteworthy and worth pursuing, would appreciate your thoughts.



http://i1210.photobucket.com/albums/cc418/mswill1/Savage%20Firearm%20Related/IMG_0635.jpg (http://s1210.photobucket.com/user/mswill1/media/Savage%20Firearm%20Related/IMG_0635.jpg.html)

http://i1210.photobucket.com/albums/cc418/mswill1/Savage%20Firearm%20Related/IMG_0636.jpg (http://s1210.photobucket.com/user/mswill1/media/Savage%20Firearm%20Related/IMG_0636.jpg.html)

http://i1210.photobucket.com/albums/cc418/mswill1/Savage%20Firearm%20Related/IMG_0637.jpg (http://s1210.photobucket.com/user/mswill1/media/Savage%20Firearm%20Related/IMG_0637.jpg.html)

[fgw_in_fla]

For starters, I'd open up the charge weights to .5gr between groups.
2nd, from what I recall when I used to shoot .243, long bullets needed more velocity to stabilize with that 9 twist.

I think Superformance is pretty slow like 4831. Maybe go higher in charge but do keep an eyeball out for over pressure.


Also, you using a bipod? Bag? Cement block? (up front)
How about on the back end?

And of course, you checked scope mounts and all that other stuff?

[mikgarus]

Check with the official OCW forum and they'll fix you right away.
http://practicalrifler.fr.yuku.com/directory#.Vnw_M_krKM9

[twarren]

I think you are pretty close with B,C,& G I would go with G and play with the OAL. JMO

[Robinhood]

Move bullet to jam and move to 300 yds. Do 3 groups on 3 targets, one charge fired at each target working round robin firing each charge at a different target. Plot each charge and look for a group on each target. you should end up with three charge weights consistently grouping closer than the rest. There velocity and vibration node is relatively consistent.

[mike21]

Thanks for the thoughts folks. As mentioned, I tried to follow as closely as possible Dan Newberry's instructions found here: http://optimalchargeweight.embarqspace.com/

My problem is trying to identify the 3 charge weights that come the closest to hitting the target in the same POI. To my inexperienced eye, the center of all 7 groups are about the same POI. Actually, when the targets are superimposed on each other, the widest POI spread for all 7 groups is .8".

My inclination at this point is to bracket my best guess at 200-300 yd to get a little separation....then do the seating depth drill for the VLD's. mikgarus, thanks for that link, I'll use it after we all settle down from the holidays.

Robinhood, sorry to loose you from the forum. Have always enjoyed your posts. For those of you that don't know, Robinhood was recently abducted by alien women and will no longer have internet access. You can read the particulars here:

http://www.savageshooters.com/showthread.php?48162-A-good-bye-to-all (http://www.savageshooters.com/showthread.php?48162-A-good-bye-to-all)

Merry Christmas all, enjoy the next few days.

[Robinhood]

From (cyber)space I will offer this. What I gave you was a hybrid of the two systems, each target verifies the other.
This is OCW
14. Triangulate the groups. This means to connect all three shots in a triangular form, and determine the center of the group, and plot that point on the target. Measure this point's distance and direction from the bullseye, and record the information somewhere on the target. Do this for all of the targets. If you have a called flyer, you should discount that shot, or replace it in the group if you have an additional round loaded with that charge.

15. You will now look for the three groups which come the closest to hitting the same POI (point of impact) on the targets. The trend of the groups should be obvious, normally going from low and favoring one side, to high and favoring the other side. But along the progression, there should be a string of at least three groups that all hit the target in the same relative point.

16. After you have carefully measured group sizes and distances and directions from the bullseye, you will know which three groups come the closest to hitting the target in the same POI. You now choose the powder charge which represents the center of this string. For example, if 34.7, 35.0, and 35.3 grains all grouped about 1.5 inches high, and about 3/4 of an inch right of the bullseye, you would choose the 35.0 grain charge as your OCW (optimal charge weight). This charge will allow 34.7 and 35.3 grain charges to group right with it. This will be a very "pressure tolerant" or "resilient" load.

Ladder test Link
(http://home.mindspring.com/%7E45-70-350/the_ladder_test.htm)

Then there is Eric Cortina and his process. All good tools.

[mike21]

.....16. After you have carefully measured group sizes and distances and directions from the bullseye, you will know which three groups come the closest to hitting the target in the same POI..........

Yep, that's exactly what I've been trying to do, but it is not that obvious. All 7 groups are about the same distance. As mentioned above, I'll come up with some combination of methods, just a little PO'ed to go thru 24 rounds of components with no resolution. Okay.... 'bout time for the Christmas turkey....later.

[LongRange]

mike...E,F and G look like your higher charge weights...you pulled 1 shot on target F but had you not im willing to bet it would have grouped right with the rest so if it were me id work between 44.1 and 44.4...your lower charge weights look to be from 43.2 to 43.8 because i bet you had some small shooter error with one of the shots on target D...im not sure what the max charge is with the combo your running but id also bet you were just on the edge of another node with your highest load.

IMHO .040 off the lands is to far off as a starting point for testing as your way off the lands and moving more than about .010 at a time may cause you to miss a good seating depth...i personally like to be a little faster so id go with the higher node and adjust .010 back(.050)and then move closer .015 at a time and shoot a few 3 shot groups and if you find a good load shoot a 5 shot group at 2-300yds to confirm.

also me being me id load 3 each at .3g higher than your max just to see if it got tighter or opened up.

[mike21]

Like you with your 260AI LongRange, I'm trying to follow the OCW program to the letter. Your thoughts are more logical than anything I have come up with. The max charge of 44.4g for a 95g bullet is based solely on a email with a Hodgdon rep that said he got it from a Hornady manual. So I'm not real warm & fuzzy with that number, especially without a chrono.

Group G at 44.7g is the .3g above max you recommended. Group center just sort of fell in there with everybody else. But like you, I plan on working the upper levels when I get back to it. Deer hunters have my reloading area/range clogged up till about Jan 4.

The jump bothers me as well, and future loads will be run closer to the lands. I'm sure you are familiar with Berger's VLD seating depth recommendation.

http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

May give that a whirl, as the VLD's are quite famous for not being a cheap date.

Appreciate your time & thoughts.

[Robinhood]

He he. Shooting Bergers and concerned about cost. You better get you some SMK's lol. Hope the turkey was good.

[mike21]

Well....I've had the Bergers a long time & they were cheap back then.:rolleyes: Plus, this bullet and powder are both new to me and will be the last combo in this barrel. When this box is used up, I plan on screwing the barrel off and replacing it with a new x-caliber in 6.5 Creedmoor I have sitting in the safe. I have most of the parts needed for another .243 except a 7 or 8 twist barrel. Will think about that build after seeing how the CM goes.

Yeah, the turkey was.....well.....turkey. I know the scientists say it isn't so, but I think I'm entering a tryptophan coma. Goodnight all.:sleeping:

[LongRange]

im not really following the OCW with the AI im actually looking for a specific velocity and then tuning from there...and i am familiar with the berger seating method and with the VLDs....the VLDs are great bullets IF you can get them to shoot...personally i never have.

if you are concerned about pressures then i think youll have good luck with the charge weights in the groups C and D area...pick one and and try adjusting your seating depth closer.

[mike21]

Oops, sorry about the gun mix up LongRange, must have been thinking about the Bartlein? Anyway, thanks for the recommendations, I'll use them.

[eddiesindian]

Id keep doing what your doing. Lots of ways to do it.
Its been my experience that the Berger VLDs have to be at the lands or a few thous. off. That type of ogive lends itself to that.
I sent more than enuff Berger VLDs down the tube to justify just that at the cost of hitting my wallet.
Id go 43.5 with the pill seated .001-.003 off the lands and see what gives.
(for me) when im getting down to the natts ass with load development. I prefer making my own targets which don't cost me anything. I use a red marker (fine point) and ruler in 3" crosshairs. (no center dot)..crosshairs from the scope to crosshairs on paper. when scope cross hairs are aligned to target crosshairs....the red marker cross hair disappears, when not?...the red appears. (for me)..that equates to movement. You,ll see vertical or horizontal movement immediately.
good luck

[Robinhood]

Is that the only powder you have? What did LR use in his 243? I have found 4831 and 4350 serves that cartridge well with those weight projectiles.

[mike21]

Hey Robin, no I have access to a fair selection of what are probably more appropriate powders. Have had the Bergers for a few years, and stumbled across a # of SuperF a while back. Just trying the combo out of curiosity....old retired guys gotta have something to do.

[mike21]

My apologies eddie, skipped right over your post earlier. Thanks alot, you and LR are pretty consistent in your advice, I'll try to put it to good use. And I suspect any Berger work in the future will be Hybrids if I can't get these to a consistent half MOA. Like your crosshair target idea, will also give that a try somewhere along the line.




Id keep doing what your doing. Lots of ways to do it.
Its been my experience that the Berger VLDs have to be at the lands or a few thous. off. That type of ogive lends itself to that.
I sent more than enuff Berger VLDs down the tube to justify just that at the cost of hitting my wallet.
Id go 43.5 with the pill seated .001-.003 off the lands and see what gives.
(for me) when im getting down to the natts ass with load development. I prefer making my own targets which don't cost me anything. I use a red marker (fine point) and ruler in 3" crosshairs. (no center dot)..crosshairs from the scope to crosshairs on paper. when scope cross hairs are aligned to target crosshairs....the red marker cross hair disappears, when not?...the red appears. (for me)..that equates to movement. You,ll see vertical or horizontal movement immediately.
good luck

[LongRange]

if you have a printer heres a ton of different targets you can print out...

http://targetz.com/targets01.htm

[schnyd112]

I will never buy another target...That is awesome! All downloaded and saved, big thanks LR.