Compressed loads (.308)

[Racalman]

What is the correct definition of a compressed load?

Is it when the base of the seated bullet touches the top of the powder, or when the bullet is seated further and the powder is forced up around the bullet?

Thanks.

[ovenpaa]

My view is it is a load that causes the powder in the case to compressed/moved when the bullet is seated. This can be anything from a theoretical compression suggested when using something like QuickLoad right through to an audible crunching when the bullet is seated.

I always try to get my load to around 95% or better case capacity with the bullet seated and choose powders accordingly and the MV can be reduced slightly by Moly coating the bullet or similar. It can be quite disconcerting when you hear powder crunching as the bullet seats and it is usually an indicator that it is time to consider a slightly faster powder.

[Racalman]

Thanks for that. I use QuickLoad with measured components so have a good idea of how full my cases are. I have no problem with slightly compressed loads (using a drop tube helps) but here's the reason for my question.

In order to try and improve my 1,000 yard scores I bought a Redding competition micrometer seating die, but only when I started using it did I see the warning that it will be damaged by compressed loads. I just wondered if there was any leeway in that!

Up to now I've been using 47gn N550 with Berger 185gn juggernauts quite safely, but have to reduce that to 45gn to avoid compression and have lost some vital MV.

[ovenpaa]

First thing to do is check the H2O capacity of a case and enter it into QL, you may find the loads are less compressed than before. QL always seems to be rather cautious about such things and you should be able to go to 104-105% without any issues with the dies. You know the load is safe however you should still work up slowly to protect the dies.

[Racalman]

OK, I've measured my components and case capacity and run QL again. For my two loads it gives me these figures for N550:

Code: Select all

47gn: 105.9% fill   98.8% burn   2673fps
45gn: 101.3% fill   97.7% burn   2560fps

I think the die will be safer if I stick to the lower load, and the MV should be high enough to ensure the bullet remains supersonic at 1,000 yards.
Or I could change powder to H4895 or RE-15 and get 2600+fps with <100% fill but I've just bought some more N550 aaarggh .