New Shooter/New OCW Test

[Coopracing]

So I have been reading a lot lately since I picked up this GAP M40. New to the precision rifles, although I have shot rifles and hunted, but have been learning and improving.

I have run this test, and now I am trying to read the test. Obviously I would like to go to the one hole target and call it good, but wanted to get some input from you guys. Not sure that some of the variances are not the operator, but I tried to be consistent. I did label the one called pull I had.

Here are the specs, and thanks in advance;
.308
175 SMK
.010 off lands
2.850 COAL
Varget Powder
CCI 200
New Lapua brass, just load and go.

I know the High load is over the book, but I did work up and had absolutely no pressure signs. Would like to get all the FPS I can. Here ya go;

 

[savageshooter86]

I like 43.9. And next try seating depth test. It appears 44.5 may be scatter node, so 1.5% from that should put OCW at 43.8 which is close to what I see on your target

Remember OCW is about finding the middle of a consistent node. So keep at it smart looks like you are headed in a good direction

 

[Twoboxer]

I'm gonna violently disagree with Savageshooter86 . . . I like 44.0

Same basic logic, but the common POIs seem to begin at 43.9, and 44.2 certainly seems fine . . . so I'd load at 44.0

 

[Sonic Crack]

Im a velocity whore so I'd go with 45.7

 

[seasprite]

I would go with the 45.1, it looks to have the same point of impact as the 44.8 and 45.4. I know its hard to ignore the tight groups but you have to, to find the OCW. Start working with the seating depth to see if you can tighten it up.

 

[rduckwor]

43.9 - 44.0 should work fine depending upon velocity. As previously posted , its time to work on seating depth and OAL.

For grins you might run a couple more 5 shot groups in the range you choose and then pick a charge weight to use for OAL tuning.

Good Luck,

 

[Dan Newberry]

I'm not 100 percent sure that pulled shot in the 45.7 group isn't actually just reaching for that other point of impact which you see at 46.0 grains. That's how the groups disperse normally... the POI moves around.

If 44.5 is a scatter node, the next one would be at 45.7 grains. And one shot is not where it should be there, for sure. I know you believe you may have pulled it, but maybe you really didn't. In either case, 45.7 is probably not going to be repeatable for accuracy.

I like what the other guys are saying... hang around 44.0 grains for the charge, then work with seating depth if you want to tune the groups tighter.

Dan

 

[Coopracing]

Thanks for all the input guys. I am not sure how much I contributed to the variances in the shots, but hopefully not too bad. I knew I was off target when the shot touched off on the 45.7 shot. I will try the 44 range. I will load up a few more in that range and see what it does. Fortunately I have a good supply of bullets and powder, and it gives me a chance to shoot more.

Thanks again for taking the time to comment.

 

[savageshooter86]

to be more sure, you can load 43.3 up to 44.5 again and verify. Or you can pick 44.0 and do seating test to find best group size THEN reshoot the charges close and it will tell you again. By changing seating depth the OCW may change very slightly, so by reshooting 1-2% above and below your charge you can be sure you are dialed in