Compressed loads in .308 with IMR 4064?

[Ray P]

Are compressed loads for this cartridge typically seen in the 43 to 44 grain load weights for IMR 4064?

Just loaded my first batch of .308, using IMR 4064. With individually measured loads in the 43.5 to 44.3gr range, I'm seeing compressed loads with 150 gr BT FMJs (Midway blems from a few years back) at COAL of 2.80. Since Hodgdon's manual recommends 43.0 grains as a starting load, and says 47.7gr (max load) is compressed, I'm surprised to see such full cases so much lower in the load band.

All charges were made from a Chargemaster, and each charge was double-checked with a separate MTM scale.

The brass I'm using is once-fired Lake City LR 01 (Long Range 2001), all full-length resized. Even though it is not crimped MilSpec, I decided to treat it as a lower-volume milspec case.

Anyway, I decided to start with the Sierra (50th Ed) manual's recommended target load of 46.1 gr, reduced by 2 grains due to military brass (now 44.1), and go a few of tenths of a grain on either side for my first shooting sample... so 43.7, 43.9, 44.1, 44.3 and 44.5. Because the case with 44.3 gr was so full, I opted to stop there & load up some 43.5s instead.

 

[rcmodel]

Sounds normal to me.

Generally speaking, if data says a Max charge is going to be compressed, that indicates two things to me.

1. The powder is too slow for the bullet weight or caliber you are using.

2. It won't be quite as full if you tap it on the bench a few times to settle the powder.

Except by the time you get to the Max load, it won't settle any more, and will actually be compressed.

rc

 

[ArchAngelCD]

It may seem like that lower charge is compressed but it's probably not. That powder doesn't settle into the case well and may seem like it's filling the case but if you tap the case a few times you will see the powder level drop.

 

[Ray P]

Thank you! Tapping the cases does help.

RC Model; 4064 probably would not have been my first choice, but it is one of two suitable powders available to me. Varget, RL15, and 335 are all generally unobtainium for this area.

 

[243winxb]

If you click print on the Hodgdon website, Hodgdon is using Winchester brass. Your Lake City LR 01 may be different in weight/volume . Your brass may produce higher pressures.

 

[SuperNaut]

I load .308 with 4064 right in that load range. Every once in a while I'll get a crunchy seating stage. The earlier comments are correct, a couple of taps on the case will get the powder to settle.

 

[MZ5]

Consider brass capacity, as 243winxb suggested. Also, pouring the powder onto the side of a slightly inclined funnel, thus making it 'circle' into the case like in a whirlpool, will pack the powder both more tightly and more uniformly than just dumping it straight down the funnel.

 

[4895]

Some people use an extended drop tube with their powder funnel to help settle the powder better. You might look into something like that. Sounds like an easy home-made project.

 

[jmr40]

That is no where near max. I'm loading 45 gr in Federal brass with no compression. You probably won't have any issues with different brass.

 

[TexasShooter59]

This link is about a similar question I asked. I found that tapping the case on the rim at a slight angle helped the powder to settle.

 

[Ray P]

Well, no crunching at the projo seating event after some Obsessive-Compulsive case tapping. I imagine this is what BPC loading is like, only with Cream of Wheat to top things off.

Thanks for the link, TexasShooter59. I did do a search before posting, but I probably didn't use the right search terms. Info about LC case volume also was helpful.

 

[balderclev]

I load 44 gr of 4064 behind a 150 gr E-Tip projectile in LC brass. I use 4064 because it is the only powder I tried that gave good groups with this projectile.

Like others, I just tap the case a little before seating the bullet.