More 255 gr data (with chrony results)

[Josh]

All these groups were shot at 50 yds and the FPS recorded was an average over the string. Recoil with the fastest load was minimal, about like a 22-250. My last group needs shot again, i had to adjust the bags in the middle and my last 2 shots went high.

 

[Ian]

Got that freight train moving right along! I see nice round holes, a very good sign.

 

[Josh]

Got that freight train moving right along! I see nice round holes, a very good sign.

How far would you go with IMR 4198 and when could i drop the filler? I plan to take this to 30 gr unless anyone has some other suggestions.

 

[Brad]

Is this an 06 or a 308? I forgot.
I wouldn't go 30 of 4198. By that point I would have gone to a slower powder, maybe 4895.
Heck, get that flying pencil up to 2000 fps and what more is needed? It should penetrate like no tomorrow.

 

[Josh]

It is a 30-06.

Would you say 27 gr then how much 4895? I am only looking for 1900 FPS. If i can get 2,000 that would be all the better.

 

[Brad]

I would be making the change soon. Velocity tells me you are generating some pressure already. I would need to do some real study of the Lyman manuals to say where I would start with 4895.

 

[Josh]

This is interesting, so far groups have went down as speed goes up. The 25 gr load would have popped em all in if i didn't adjust. Primers looked good on both 4198 loads, I know that isn't a complete story though.

What if I went to IMR 4064 or IMR 3031at roughly 30 gr and a filler? Pressure would come down... I don't have Varget or i would try there.

 

[Ian]

Definitely stop increasing the 4198. I'm thinking a medium-slow double-base powder to get to 2K fps while keeping launch pressure low. Plan on using Dacron and try to find something that will keep the loading density in the 70-80% range. I'd be trying H414 or slower.

 

[Josh]

Ok I have been looking over data and I am going to start with 25 gr of IMR 4064 and work my way up to the 1900 fps goal. Hopefully around 28-30 grains I can rid of the filler unless it aids in accuracy.

Anybody know when the 6.5 Cruise missile started to bend and twang off in flight?

 

[Ian]

I wouldn't rid the filler unless you go to at least 80% loading density. Might want to read up on "Secondary Explosive Effect".

As for the Cruise Missile, I've never known them to bend in flight myself and I've shot them to over 2700 fps, paper-patched in a .270 Winchester. In the Swede they can yaw pretty badly and become unstable enough to make some impressively big groups if not loaded correctly, but I don't buy the 'bending' thing. I've only known one person personally who actually had one come in two in flight, maybe it bent enough to break, who knows. He goes by "Nobade" and happens to be a member here and might weigh in with details. The CM does take longer to stabilize (yaw precession) due to the fat nose, length, and wide lube grooves, and large meplat (CG/CP imbalance), but if launched as straight as possible will eventually fly straight, though it might take more than 100 yards for the holes in the paper to start showing up round.

 

[Josh]

I know what "SEE" is, i have had some hangfires with cast, the general consensus is cast is very unlikely to produce a SEE explosion, I read up on this a lot when researching 4831 and cast bullets. This may not work for my bullet because of weight and bearing surface, either way a small amount of filler is of little issue, just a "goal" to not need it.

I have never played with the 6.5 CM but have heard "the stories" and mine is getting long for diameter.

Once we get all of the data brewed up and goals reached (or not) I plan to make one fluid thread about it. Lots of info about shooting cast in an 06, but just about nothing for pills over 230 gr.

This is a great learning experience and I want to thank the guys who have given input on this experiment.

 

[Ian]

It's fun to watch you do it, too, we all learn a lot seeing what happens actually when educated guesses are put to the test. SEE was worth mentioning in case you weren't familiar with it, and you are certainly looking at going into the territory where it should be mulled over as you consider building starting loads.