Looking for a little help with my 338 win mag

[dfrombc]

Today I was out at the range fine tuning a load for my 338 win mag. I have the load pretty much dialed. Today I was looking to dial in my 200m zero, verify my actual drops out to 500m and figure out my velocities working back from those drop #'s.

The gun is a custom built 338 win mag. Pre-64 model 70 receiver, 22'' barrel (unkown maker) in a wildcat stock. I'm using winchester brass, varget powder, fed 215m primers and barnes 210gr ttsx. The barnes website states a max charge of 60 gr of varget for a velocity around 2800 fps in a 24'' barrel.

I'm loading 62.2 gr of varget. The gun shot a consistent 3/4 moa (3 shots, 100m) at 60 gr but I wasn't seeing any pressure signs at all. Being curious I worked up to 62.5 gr. Still no pressure signs and still shooting under 1 moa. The only difference in the groups is that there is less vertical in the 62+gr loads. I went with 62.2gr for my hunting load and this is what I had with me today.

After shooting steel and keeping track of my actual come up's I plunked the #'s into my ballistic app and it came back with 3139fps. Now according to the manual that is 300fps faster than their max load from a longer barrel. Here's a picture of the case heads. I don't see excessive pressure and bolt lift is effortless.

I'm looking for opinions on whats up. Problem with the software? Dangerous loads? Fast barrel? Am I missing some obvious pressure signs? I've reloaded for a few years now and have seen excessive pressure before so I'm not totally green.

 

[Eagleye]

I think you need to run that load across a chronograph. Calculating velocities from drop figures is sketchy, in my experience.

Don't see any obvious pressure signs, but 3139 with a 210 grain bullet is not likely correct. [particularly with a 22" barrel]

I have shot and loaded for many 338's, and cannot remember seeing 210 grain velocities quite that high in any, even with 26" tubes.

Additionally, Varget would definitely not be my first choice for max velocity. I would be reaching for a bit slower powder. [Reloder 19 or IMR 4831 comes to mind]

Have you measured case expansion across the belt with a good vernier micrometer? [compare a new case with one fired with your load]

Regards, Dave

 

[cdn moose]

For Eagleeye

Not to hijack this thread but what should a guy be looking for as far CHE goes? I'm seeing a lot more than the 0.0005 I've read about so many times! I've not measured a once fired case that has been reloaded, only new to once fired, not a 338WM either but a Whelen. Nosler brass. Just looking for an opinion from someone with a heckofalot more experience than me!!

Thanks in advance, Moosey

 

[dfrombc]

I think you need to run that load across a chronograph. Calculating velocities from drop figures is sketchy, in my experience.

Don't see any obvious pressure signs, but 3139 with a 210 grain bullet is not likely correct. [particularly with a 22" barrel]

I have shot and loaded for many 338's, and cannot remember seeing 210 grain velocities quite that high in any, even with 26" tubes.

Additionally, Varget would definitely not be my first choice for max velocity. I would be reaching for a bit slower powder. [Reloder 19 or IMR 4831 comes to mind]

Have you measured case expansion across the belt with a good vernier micrometer? [compare a new case with one fired with your load]

Regards, Dave

I don't believe for a minute that I'm getting over 3100fps out of it. A crony would be ideal but mine died not long ago, haven't replaced it yet. Guess I better start searching the "best crony'' threads !

I started with H4831 but couldn't get near a max load in the case when seated just short of mag length. I had a few lbs of varget kicking around so I figured why not? It seems to shoot very well out of this gun. Everybody raves about RL19 in the 338 but I was't smart enough to stock up and RL powders seem pretty hard to come by these days. I'd like to try to use the varget up for now.

As far as measuring the case across the belt there appears to be 1 thou difference between a new unsized case and the fired brass from today. Keep in mind I'm using cheap digital calipers to measure this. I doubt they can be relied upon to accurately read down to the 0.001" or less

 

[mbogo3]

Data for RE#19 and loads for H4831 were pretty much interchangeable weight /accuracy wise in my .338Win Mag but may not be in your's...........Harold

 

[Eagleye]

The powders that I have found worked best [for me] in the 338 are as follows:

Up to 200 grains: IMR or H 4350, Hybrid 100V, IMR 4451, W760/H414, Vihtavuori N550.

210-250 grains: IMR 4831, H4831, Reloder 19, Norma MRP, Reloder 22, Vihtavuori N560, AA3100.

Norma MRP has usually given me the highest velocities with the 210/225 grain pills, with Reloder 19 and 22 close.

Regards, Dave

 

[dfrombc]

Thanks for the help Dave! I'll be keeping an eye out for those powders in my travels. I think I'm going to round up a crony and see what it tells me. I'm sure it's not loaded hot enough to be unsafe. I was most worried about possibly missing pressure signs. The load seem to be flat shooting despite being handicapped by using varget (varget should produce the worst velocity according to the barnes manual). Provided I'm in the 2750 - 2800fps range I will be happy ........ for now anyways!

 

[dfrombc]

Well I went back to the drawing board. I annealed the used brass that came with the gun and something changed. The gun was shooting MOA with varget out to 200m and after the annealing group size doubled. I decided to scrap the old brass and find a more appropriate powder. As luck would have it I found 2 lbs of H4350 and a fresh bag of winchester brass at my local gs. I used the OCW method to zero in on a node. It seemed to show up between 70.6gr and 72 hr of H4350. I went back to the bench and loaded 4 rounds in 1/2 gr increments between 70.6 and 72. I always load 4 when doing this because I always seem to pull one from the group. Shooting a 7lb 338 doesn't help either. I'm happy I did because I pulled one out of at least 2 of the groups. Long story short I seem to be on the right track. POI seems to be pretty consistent between 70.6 - 71.5gr. I'll retest 71gr out to 500m and hopefully be off to the races!

Targets were shot at 100 yards

Thanks again to Dave for the advice!