OCW noob help

[endlesscoffee]

So I ran an OCW test the other day, but was unable to get the velocities as there were a lot of shooters on the range and my LabRadad kept picking up the other shooters. Below is what I ended up with.

Rifle R700 S.A.C Trued
Barrel: Bart 1:10 22"
Bullet: 168 SMK
Case: Fed 1x fired
Powder: Enduron4166
Primer: Fed #215 LRP-M
C.O.A.L: I tried to do 2.8, but I learned I need a comparator.
Purpose: using these 168s I have on hand for practice rounds in alt positions this winter. I'll use a heavier round or bergers for comps.

first group was factory 168s to warm up. Second was a set of sighters. The rest worked up from 40.8 to 42.8.
Hodgden listed max for 4166 at 43.5. I stayed conservative below that due to the LRPM. I didn't have any pressure signs I could notice, but I did have a couple of rounds that had easy bolt lift with a difficult time extracting the casing(maybe didn't get sized quite right?) 1 round in 41.3 and 41.6.
Currently with my new-reloader self I'm thinking 41.3 seems like a good start, but the velocity I got off 2/3 rounds was 2594. I think I should try to get a higher fps. Maybe run another smaller OCW between 41.3-41.8?
As I can see in 42.0, 42.2, 42.5 it seems 1 round keyhole in each group.
Thanks for any tips and help.

 

[nn8734]

I’d do 42.2 and 42.5, chrono them and see what happens. Two five-round groups each at 100m should give you enough info to move forward beyond that.

Assuming you pick, say 42.5g as the charge weight and no pressure exists, load up 40-60 rounds and start building out a validated dope card at known distance starting at 150m (or yards) in 50m increments until you reach as far as you’re going to take it.

Done

 

[endlesscoffee]

I’d do 42.2 and 42.5, chrono them and see what happens. Two five-round groups each at 100m should give you enough info to move forward beyond that.

Assuming you pick, say 42.5g as the charge weight and no pressure exists, load up 40-60 rounds and start building out a validated dope card at known distance starting at 150m (or yards) in 50m increments until you reach as far as you’re going to take it.

Done

So looking at 42 and 42.5 is there something that would cause them to keyhole like that in particular that I would be able to avoid or is that possibly due to another factor. I forgot to mention it was raining pretty hard during this.

 

[nn8734]

That’s how the paper ripped when the bullet passed through. Retest at those cws and assess the results preferably on a nice day

 

[spife7980]

Yeah I know to not go chasing groups but I would still see if you can do that 40.8 again next weekend. Speed my butt, thats a hole.

 

[TheOfficeT-Rex]

Put your targets on a clean/fresh cardboard backer. It will get rid of a lot of the tear out. I doubt it's actually keyholing.

 

[endlesscoffee]

Yeah I know to not go chasing groups but I would still see if you can do that 40.8 again next weekend. Speed my butt, thats a hole.

I know that too, but you're right. It's promising, but I think I was about 2400 fps with that haha.

 

[endlesscoffee]

Put your targets on a clean/fresh cardboard backer. It will get rid of a lot of the tear out. I doubt it's actually keyholing.

That makes sense. I'll try and piece them together when I get home and look closer.

 

[mtang45]

Depending on what LRPM means, I would run again with loads from 42.8 to one or two ticks above book max. Evaluate each shot for pressure. AND, remember you are not looking for group size with an OCW, you're looking for consecutive loads with very similar POI.

What is the acronym LRPM?

 

[endlesscoffee]

Depending on what LRPM means, I would run again with loads from 42.8 to one or two ticks above book max. Evaluate each shot for pressure. AND, remember you are not looking for group size with an OCW, you're looking for consecutive loads with very similar POI.

What is the acronym LRPM?

Large Rifle Primer Magnum. I figured I wouldn't want to run too close to max as I've read that mags can increase the pressure. With 4166 being fast burning already, I figured it was best to be conservative. If I'm misinformed please correct me!

 

[Evintos]

Depending on what LRPM means, I would run again with loads from 42.8 to one or two ticks above book max. Evaluate each shot for pressure. AND, remember you are not looking for group size with an OCW, you're looking for consecutive loads with very similar POI.

What is the acronym LRPM?

Federal 215's are large rifle magnum primers. Letters are usually LRMP though but 210M's also use LRMP (Large Rifle match primer).

@endlesscoffee You can probably push a bit more before you hit compressed loads around 43.5gr if you want to chase velocity considering you haven't seen pressure signs at 42.8gr.

 

[endlesscoffee]

Federal 215's are large rifle magnum primers. Letters are usually LRMP though but 210M's also use LRMP (Large Rifle match primer).

@endlesscoffee You can probably push a bit more before you hit compressed loads around 43.5gr if you want to chase velocity considering you haven't seen pressure signs at 42.8gr.
View attachment 7719719

Oh thanks for the clarification on LRPM vs. LRMP. I might load up some from 42 and go from there. I was worried the magnums would add additional pressure.

 

[Evintos]

Oh thanks for the clarification on LRPM vs. LRMP. I might load up some from 42 and go from there. I was worried the magnums would add additional pressure.

You got the right idea. Generally speaking magnum primers will exhibit pressure signs earlier compared to the same charge weight with standard primers. However, since your current load work up with the Federal 215's has no pressure signs, it's ok to go higher. You could load some rounds in 0.2gr increments up to 43.4 (and some at 43.5 if you wanna deal with compressed loading) but keep an eye out for pressure signs on the once you go above 42.8. If you start seeing pressure signs at for example 43.2gr, stop right there. You'll have to pull bullets out of the rounds you loaded above that charge weight to reuse components. You also may reach compressed loads (max case fill) without even seeing pressure signs. Lots of variables to it.

 

[charnicus]

I’d test again in the 42 + range. If you wanted to get more scientific try that range with some different seating depths. That 40.8 group is beautiful. Two of my loads with Varget, and H4895 and two different bullets are right at 42 grains. I see no reason for you to chase anything higher unless you want to for fun.

 

[mtang45]

Large Rifle Primer Magnum. I figured I wouldn't want to run too close to max as I've read that mags can increase the pressure. With 4166 being fast burning already, I figured it was best to be conservative. If I'm misinformed please correct me!

You have it correct, start low and work up. However I think you have room at the top since you noted no pressure indicators. Thanks for the LRPM explanation (I knew that ). I guess I had not read LRPM in context of loading conservatively before.

Can I ask why you are using magnum primers and not standard Large Rifle?

 

[Changed]

In my experience 4166 reaches pressure before Varget does. So don’t expect to get to 44/45 grains.

Stop shooting OCW, and do a good old fashioned pressure test. Literally increase your charge until you see pressure. Figure out a safe charge weight/velocity in that range and do a seating depth test at that charge weight.

Chasing an optimized charge weight will only waste time/components.

 

[endlesscoffee]

You have it correct, start low and work up. However I think you have room at the top since you noted no pressure indicators. Thanks for the LRPM explanation (I knew that ). I guess I had not read LRPM in context of loading conservatively before.

Can I ask why you are using magnum primers and not standard Large Rifle?

I got 1k when things were really scarce. Figured I might as well use them during the winter

 

[endlesscoffee]

Well I ran another test with all of your feedback with a few select groups. Tested the 40.8 again, 41.3, 41.5. Then jumped up to the 42 series. 42.2, 42.4, 42.5. Looks like I found a winner with 42.2. Might play with seating depth a bit, but I think for the winter sessions I'll just run as is.
Thanks for everyone's help.