OCW - Should I Commit, Is this the Right one for ME?

[pmclaine]

First I dont really like load development. I just wish I could know the perfect load and start firing 1 MOA minus groups like the government prints paper.

Ive been working on a load for my LMT MWS, .308 win, 16 inch chrome lined barrel. Im working with Nosler 168 grain Custom Comps, Winchester Large Rifle primers, IMR 4064 and once fired WCC 13 brass.

My first OCW looked as follows



I went 41.9 for an initial load but wasnt impressed at 300 yards. I thought I needed to be heavier with my powder. I dont have a Chrony so I have no idea what FPS Im loading to.

I made up another OCW run that looked like this



From this I decided to make up some 41.8, 42.6 and 44.2 and go to 300 yards. I shot 2,2 and 3 at the center bull for sighters. Than 5 at each bull as marked.





42.6 is the first time my LMT has been under 1 MOA. Even at 100 Ill typically get 1.25 or 1.5 MOA. At 300 it has been a pretty consistent 2 MOA rifle using some remanufactured Atomic Ammo with a 168 Nosler CC over Varget rated at 2600 fps.

So does it look like 42.6 is the one or just a fluke? Ill be making another batch of rounds to try out. It would be just nice to know if the OCW targets and 42.6 seem to follow the OCW expectations.

 

[Darkside-Six]

So, you're running an OCW test with 5 rounds? Are you firing round robin or just firing groups? What twist rate is your barrel?


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[pmclaine]

The LMTs CL use a 1:10.

I fired the first OCW using 5 rounds in a round robin fashion, single loading. I fired the second OCW using three rounds in a round robin fashion, single loading.

Today at 300 I fired five in each target from the mag. Conditions were pretty tame so there wouldnt be environmental factors to consider one group to the next. I allowed a barrel cool down between groups. The 44.2 load blew one primer, flattened the rest and the recoil was "stout" compared to the other loadings.

 

[Darkside-Six]

Well you really need to chrono them but I think you're right on with the 42 mark. I wouldn't judge the performance so much on your 300yd results as that could be shooter error. If you have the slightest error in your mechanics it won't show up too much at 100 but you'd see it more at 300. I think you have the right idea at 42 gr

I also use 4064 for my 308 loads pushing 175 SMK's. When I first did my load development I ran a ladder test at 300 and came up with 44.5 but wasn't happy with it. After I ran my OCW I found my accuracy node was at 43.5. A full grain lower at a little slower on the MV than is like but it's steady and accurate all the way out to 1k. Sometimes them lighter loads are the better ones.


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[pmclaine]

Well you really need to chrono them but I think you're right on with the 42 mark. I wouldn't judge the performance so much on your 300yd results as that could be shooter error. If you have the slightest error in your mechanics it won't show up too much at 100 but you'd see it more at 300. I think you have the right idea at 42 gr

I also use 4064 for my 308 loads pushing 175 SMK's. When I first did my load development I ran a ladder test at 300 and came up with 44.5 but wasn't happy with it. After I ran my OCW I found my accuracy node was at 43.5. A full grain lower at a little slower on the MV than is like but it's steady and accurate all the way out to 1k. Sometimes them lighter loads are the better ones.


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I should be going with 175's but Im trying to keep supplies from being too mixed up and getting the savings of buying in bulk for my M40A1, Garand and 1903's. Only rarely will I shoot beyond 300 so the 168 wont be falling apart on me at the distances I will use it.

What are the stats on your rifle is there any extrapolation to be gained from your barrel and my 16 inch CL? Too many variables. Different bullet different gun.

Id like to keep my brass in good shape. 44 will certainly limit its life a moderate load will be good for brass, rifle and powder supply while still having plenty of punch to get through paper. Im not good at reading OCW. Do my too OCW targets indicate a sweet spot at the 42.6 area or have I chosen a narrow node that will fall apart with the slightest change in any one factor?

 

[Darkside-Six]

I should be going with 175's but Im trying to keep supplies from being too mixed up and getting the savings of buying in bulk for my M40A1, Garand and 1903's. Only rarely will I shoot beyond 300 so the 168 wont be falling apart on me at the distances I will use it.

What are the stats on your rifle is there any extrapolation to be gained from your barrel and my 16 inch CL? Too many variables. Different bullet different gun.

Id like to keep my brass in good shape. 44 will certainly limit its life a moderate load will be good for brass, rifle and powder supply while still having plenty of punch to get through paper. Im not good at reading OCW. Do my too OCW targets indicate a sweet spot at the 42.6 area or have I chosen a narrow node that will fall apart with the slightest change in any one factor?

Well, the longer the barrel the more velocity you can generally get out of it with the same powder weight. Mine is a Schneider M40 barrel with 1/12 twist.

The purpose of an OCW test is not to see what groups best, but rather which has more shots toward your point of aim. in your case, you have a node at 42 which is a tight group, AND it's right at your point of aim so that is your sweet spot.

 

[pmclaine]

I was hoping the OCW would find a load that was good for both a Schneider M40 and this LMT.

The M40A1 shot these two OCW







The M40A1 seems to put everything in the same spot no matter what the powder charge. Im really liking 43 grains for the 24 inch barrel. I cant read OCW well enough to determine a node or scatter node and the LMT doesnt really group the way the bolt does.

Im concentrating on the MWS right now because in a week or so I intend going here



Last time I shot the M40a1 at this range but with the temp Weaver scope (hellllllloooooo USO lets build some MST100's) I ran out of elevation at 700 yards and most of my close in shots were made by holding off the silhouettes rather than uncapping and dicking with hunting turrets.