I have a .9mm carbine for competition and am trying to work up a recipe, I'm using the 125gr. blue bullet, with tightgroup and am determined to figure out a good working recipe. I worked some up at 3.9 gr. but that was way too hot and was having ejection trouble. I worked up some at 3.3gr. and a COAL of 1.130 and they worked a little better, but still having ejection problems. Wanted to know what people are using, 16" barrel, using the JP silent captured spring and bolt kit. Need some advise.

With just one powder and one bullet weight for your tests...................

You only have fps and OAL to work with to develop a load.
If your weapon does not like the bullet or the powder, you have a problem.
Plus you will need a lot of test loads to find the "Sweet spot" in fps and OAL.

You might end up having to try a different powder or a different bullet weight or brand.
Your company advised Hodgdon for data but it only had a lead bullet at 1.125" to 30,400CUP.
One of my bullet makers has 1.06 to 1.14" OAL as being usable in the bullets seating for it's 125gr.
You might ask the Company what they have as a minimum and maximum OAL for this bullet.

PS:
You did order the RN instead of the Truncated design, right ?
Good Luck.

Did you check these rounds with a case gauge prior to shooting them? I'm just wondering if the cases themselves are slightly bulged at the bottom, causing them to be harder to extract. Might want to check your sizing die setup, and what your crimp is at, as either of them can cause extraction issues.

Personally I think 125's are a bit too heavy for a carbine. The heavier weight bullet in the longer barrel does jack up the pressure's a lot more than a shorter pistol barrel. That I believe may be the reason why your felt recoil seemed "hot" and the ejection failures most likely due to the reduced velocity of the powder charge you're using.

I'd suggest sticking with 115 FMJ's for a carbine. My recipe (straight out of Speers reload manual #14) that I like a lot and use in USPSA is as follows.

Berry's 115 FMJ
COAL 1.135"
Titegroup 4.4gr.

This will put you around the 1100 fps range and I'll bet you the recoil will feel less. The ejection part may or may not be due to the cases... I think it may be the reduced charge you're using, but double check your seating die and the crimp I use is set just enough to leave a tiny shiny "ring" on the mouth of the case.

Bullet weight probably is more dependent on barrel twist rate than powder selection.
Tom