Gateway 115 gr load for M&P Shield

[Easypick]

I have some Gateway 115 gr RNBB bullets that I want to load for my 9mm Shield. Doing some preliminary dummy loads it looks like from the "plunk" test, I need about an OAL of 1.07. This is shorter than the 1.1 that I have been using when loading Berry’s using 4.3 gr Win 238 for my other 9mm. How much should I drop the load back to start?

 

[grogetr]

Measure the 2 bullets length to see what the difference is. This will tell you the difference in case capacity between the 2. Your oal difference is .040" but inside the case could be different. That will help you decide what the powder charge needs to be. Hope this makes sence. Welcome to THR lots of good help here.

 

[Steve C]

How much should I drop the load back to start?

Every manual recommends reworking up your load when you change any of the components. That means dropping back to the start (-10% of maximum). It's a pain to do but its the only way to be safe and get the best load.

If you only have a few of the new type bullet and no plans of getting more then use them for plinking and practice, load at the start level and don't worry about work up.

 

[Easypick]

Thanks for the replies. I did measure the bullet lengths and I am only seating about 0.01 deeper. As a novice, I was fixating on the OAL and not the seating depth (case capacity). I will drop back and work up the loads with the Gateways as I did with the Berry's just to play it safe as well.

Great forum with lots of good advice.