308 Reloading, Federal Brass, IMR4064, bullets 'jamming' at 45.5gr
- Thread starter blsonne
- Start date
Yep, I saw that data sheet, and it does not conform to reality on the ground right here right now 
I've got boxes of those rounds, and the powder measurement is not the same at all, or they've tweaked the recipe since then, or IMR has changed their powder, etc.
I've got boxes of those rounds, and the powder measurement is not the same at all, or they've tweaked the recipe since then, or IMR has changed their powder, etc.
Well there is your problem. You are not getting enough neck tension to hold the bullet in place with a compressed charge.
Take the mandrel out and spin it in a drill while holding some fine sandpaper on it to reduce it's diameter. That is LEE's answer for your problem.
My advise would be to take that die and chuck in a drawer somewhere to collect dust and use a regular die to partial-size your cases.
Well, 'Boo was right about not getting enough neck tension. After taking a class on reloading as part of the ORA winter training course and having the opportunity to talk with people on Saturday, I learned a good bit. Went home and pulled the bullets out of all my loads and started from scratch.
I started at 10% under max load (fudged it to 41gr for making life easier) and worked up in .2gr increments, and heard the powder crunching around 43.4gr (I love listening to music when I reload, but I'm thinking that might not be a good habit when you're starting out 'cos you'll miss some important cues). Figuring that compacting was still happening before that and I only just heard it now, I measured with one of those hornady bullet comparators on my micrometer (man that thing is great, thanks Bob!) and noticed that from 42.8gr and up the overall length was increasing steadily.
I did all of this after taking 3 rounds of the sierra federal gold match I'm trying to duplicate and measuring them for base-to-ogive and around the neck. Then I pulled two of the bullets and measured the powder for ####s and giggles; whatever it was came out to 42.2gr on both loads (vs that sierra data card image I've seen floating around that has a charge weight of 41.745gr). Now I had some simple specs for copying them based on measured lengths, and could verify seating depth based on marks on the bullets, and tension (as a function of neck diameter).
I'm now confident after learning to measure things properly and double checking all my dies that I've got things right, and wanted to post more details to help out any other noobs if/when they come across this. It is impressive the number of variables that come in to play or might be taken for granted and making "knock offs" of your favourite ammo is not as simple as you might think! Don't be afraid to pull the first 100 rounds you make and redo them because you made a mistake.
I can't wait to shoot these (I'll stop at 42.8gr or maybe 42.6gr), though I'll be wearing my ansi googles and checking for sticky bolt lift, heh. I don't want a bolt in the neck like that poor bugger with the 338 and the cleaning rod :/
I've got more Varget then I got IMR4064, and since it's colder, I'm thinking about trying another run using Varget (though I didn't hear a lot of love for Varget when pushing 175gr bullets in a 26" 1:12?). Or trying a drop tube to help the load compact itself. This is fascinating and a ton of fun
I started at 10% under max load (fudged it to 41gr for making life easier) and worked up in .2gr increments, and heard the powder crunching around 43.4gr (I love listening to music when I reload, but I'm thinking that might not be a good habit when you're starting out 'cos you'll miss some important cues). Figuring that compacting was still happening before that and I only just heard it now, I measured with one of those hornady bullet comparators on my micrometer (man that thing is great, thanks Bob!) and noticed that from 42.8gr and up the overall length was increasing steadily.
I did all of this after taking 3 rounds of the sierra federal gold match I'm trying to duplicate and measuring them for base-to-ogive and around the neck. Then I pulled two of the bullets and measured the powder for ####s and giggles; whatever it was came out to 42.2gr on both loads (vs that sierra data card image I've seen floating around that has a charge weight of 41.745gr). Now I had some simple specs for copying them based on measured lengths, and could verify seating depth based on marks on the bullets, and tension (as a function of neck diameter).
I'm now confident after learning to measure things properly and double checking all my dies that I've got things right, and wanted to post more details to help out any other noobs if/when they come across this. It is impressive the number of variables that come in to play or might be taken for granted and making "knock offs" of your favourite ammo is not as simple as you might think!
Don't be afraid to pull the first 100 rounds you make and redo them because you made a mistake.I can't wait to shoot these (I'll stop at 42.8gr or maybe 42.6gr), though I'll be wearing my ansi googles and checking for sticky bolt lift, heh. I don't want a bolt in the neck like that poor bugger with the 338 and the cleaning rod :/
I've got more Varget then I got IMR4064, and since it's colder, I'm thinking about trying another run using Varget (though I didn't hear a lot of love for Varget when pushing 175gr bullets in a 26" 1:12?). Or trying a drop tube to help the load compact itself. This is fascinating and a ton of fun
Last edited:
samsplacci71
Regular
- Location
- Toronto area
The .308 case is inherently small so for sure as you crank it up they will become compressed. I've not exceeded 42 gr. of H4895 in any of my .308 cases yet as I am only punching holes at maximum of 200m. I agree with Sunray, dump that last one and do over.
