Home Forums Reloading Reloading Software Quickload Problem w/ 22-250 and H380

I just started working a load up for my 22-250 and was entering the info into Quickload to try to get a velocity prediction. I'm using 39 gr of H380 powder with a 55 gr Vmax bullet, the problem is when I enter this into QL it's showing an over pressure condition (all manuals and the powder container specified 41 grs as the max) and a 104% case fill even though this isn't a compressed load. Am I missing something? I updated my software about a year ago if that makes a difference.

Have you measured the actual case capacity, length of the case if not trimmed, bullets for their weight and length, and actual OAL? These are factors that will influence the pressure predicted.

An example would be:
Using defaults, QL says my .22-250, using 36 grains IMR-4895 and a 50 grain BlitzKing, seated to default OAL would have 55,368 psi pressure and 3850 fps velocity.

Actual measurements of components are:
Case capacity-default says 43.49, mine are 45.2
OAL length-default says 2.350" , I can go 2.468" (.010 off lands).
Bullet measurements were:
Default--.786", 50 grains.
Actual--.785", 50 grains. (very rare for one to weigh exactly what the manufacturer says).

This resulted in a QL prediction of 48,458 psi and 3724 fps. Which, by the way, was only -13 fps off, and a quick tweak of Ba brought this in line.

I haven't measured the water capacity of my case, the OAL and case length are the same. I'll have to go back and double check the measurements on a 55 gr Vmax to see how close they are and check the water capacity.

This is the first time I've used H380 powder with Quickload...is there an easy way to verify the propellant properties are close to correct?

No real way to verify other than firing, but it should be within 5%. I have a 3 lb can of 296 that is faster than QL's default, I found that by firing a known load with only that lot of powder as a difference. After adjusting for burn rate, I was back in business.

The only problem there is that I have tried some N110, and it shoots so much more accurately and cleaner than the 296 that I don't want to use the 296 now!!

Of course, what that means is that I have to buy a pistol that likes 296.

Find the capacity, it has a pretty good impact on the pressure prediction.