Couple pics here, one new, one old. Looks identical to me. First one is the 8th or so round out my rifle. Fella told me was under pressured, to load a bit more powder. He was right, never experienced this again....
till today.
looks very similar to my eye. Swirled soot on case and everything. Same load of powder I have been using for awhile now, 103 hrs Retumbo under 300gr Berger EH. Been trying to find answer to really high velocity spread, thought to try different primer. Switched from Federal 215 to CCI 250. First shot this A.M. good, POI very close to POA at 925yds, cold bore. Second shot , dented case. Am I seeing similar evidence here? Comments welcome, need more experienced eyes here.
Just by changing primer ?
- Thread starter Gregg C
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lancetkenyon
Well-Known Member
What cartridge? Looks like a .338-378 Weatherby maybe?
If it IS a .338-378 Weatherby, your 103gr load is below suggested starting loads, so could easily be an under charged load and cause this issue. 105.5 to 111.5gr Retumbo per the Berger book.
If it IS a .338-378 Weatherby, your 103gr load is below suggested starting loads, so could easily be an under charged load and cause this issue. 105.5 to 111.5gr Retumbo per the Berger book.
Correct, it's a 338-378 Wby . Crazy how different listings/books show different data. Hogdgon online starts at 100, with 106.5 on the high end. At any rate, using Fed215 primers, this lot of powder is delivering 2980fps in my rifle. 104.5 was a hot load, at 3050. But apparently the CCI 250 was a lot cooler ignition. You have any thing like that in your experience ?
lancetkenyon
Well-Known Member
31" vs 26" (which is probably what their data is from) could easily give you 150+ fps in that case. But if you are getting pressure with 1.5gr more, I don't know how much harder I would push it (even though it IS a .338-.378 Weatherby!). How much difference in speed did you register between primers?
Yeah, I got lazy and didn't set up the chrono. POI was really close at 925yds. Elevation on first shot was dead on, in fact, to Shooter come up. Some how the second shot failed to get on video, since I didn't restart the camera, but it was at least on the rock. I think I'm just going to pull the shells apart, do the necks again and go back to Fed215.
You are getting click boom ignition because the CCI primers are not robust enough to fire off that much powder. Try a Winchester mag or go back to the Fed 215 and this will go away. I have tried CCI 250 in a number of large capacity cartridges like the 7 Rum, 460 Weatherby, 375 Ruger and have had many with the delayed ignition and quite a few where the powder didn't go off at all. The primer went off and powder was clumped and part burned but no bang. The colder it is outside the more often it happens.
You SD issues are either insufficient case fill or variable neck tension (try annealing and or neck turning to even up your neck tension). Quick cheat to check if it is the neck tension is to put a light crimp on some test loads and see if this drops the SDs. Rarely is it caused by primers unless the primer is way under powered as in this case.
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Yessir, I went back to Fed215. And funny you mention that about neck tension- decided last night to attempt bringing necks to a more uniform tension. Who makes a crimp die for that beast, do you got any idea ? Trying to avoid custom dies on a guess, ya know ?
Your standard RCBS or Redding seating die should be able to crimp, unless you are using the competition seater. If you have the comp seater the cheapest crimp option would be to just buy a RCBS standard seating die. Lee makes a crimp die for the 340 Weatherby and the 30-378 so you could check with them, they will make lots of one of dies no problem. The 340 Weatherby crimper or 338 RUM crimp die, both of which are stock items, should be able to be adjusted to crimp your 338-378 round.
Have you used one of these ? Found one for 338 RUM, cheap.
I have used the Lee ones to do 45-70, 38-55 and 375 HH and a couple of others. They do a real nice job and they are far less picky about neck trim length than the built in Crimper on a RCBS or Redding standard seating die. You won't have any quality problems with Lee dies, they are amazingly good stuff despite there low price. (Not true of all Lee stuff but their dies are great). Their collet neck sizer dies will produce zero run out necks for far less money than a comp bushing die.
That's good to know. It appears they are case specific. One custom is 75.00, but if it will help with runout, too that is actually pretty cheap. Have to go custom for a bushing die, as well. At least as far as I can tell. Looked at Redding, and Forster, it's not a standard piece for big Wby case. Probably need to turn necks to get the most out of it, do you think ?
