Did my first round of 350L testing yesterday. 12" Faxon, pistol length gas. Ammo kept in shade, but it was 80-85* and sunny. Nearly 2900'DA.

I had two factory loads, both Winchester, the 145gr ball and 180gr PowerPoint. The ball clocked in at about 2kfps, and the pp's at 1950.

My own loading of the 180gr PP topped out at 25.7gr of lilgun (federal AR match primers for all loads) for 1958fps average. I have higher charges loaded (by accident as I look back, but my pressure signs concur with Hodgdon data), but stopped there.

The 165gr FTX, again with lilgun, seated to 2.260", yielded 2030 with both 23 and 23.7gr, 2068 with 24.3gr, 2055 with 25gr, and 2037 with 25.5gr.

The 24.3 and 25gr groups were about 1" for 3 shots at 100yds. 25.5gr was about 2.5". All others got lost in previous impacts.

I find it very odd that they seem to just top out at call it 2050fps. Guess as the charge went up, so did the groups, and muzzle blast/report. Ejection also got more violent. The cases (all virgin winchester with AR match primers) showed no primer cratering, excessive flattening, or ejector marks. Obviously these loads are hot, exceeding the velocity of the factory ammo 20gr lighter.

Is it normal for this to occur? Just running out of barrel to burn the powder? I have no intention of using this caliber in a longer barrel, and all cycled the gun. For now my plan is to do a more narrow ladder, with charges of 24.8-25.2 in .1gr increments. Use whatever has the lowest SD if the charge weight doesn't effect velocity significantly.

Side note: holy shit is this gun quiet! I took the first couple shots with the wife and brother 50yds back. They both said something. I could hardly hear it over the action noise with earplugs. It's a hunting riflepistol so I figured I'd hear it eventually, and the 180gr factory loads didn't even make my ears ring from 2yds away. They barely rang as the shooter. It's going to be stupid quiet once I get the bushwhacker on it, we're going for a conjugal visit in a couple weeks, so we'll see.

The funny thing is when I built some longer length barrel bolt guns the velocity didn't go up either . Anything 20 - 26" there was any real gains in FPS.  
With a 24" barrel and Silencer co Harvester can it sounds great.

What kind of numbers were you getting in the real world?

We all know the advertised velocity is always way off, and reloading data is usually pretty far off too.

IIRC Hodgdon says a 24" with lilgun and 180gr will top out at 2200, and I'm pushing 2k with literally half the barrel length. 10% loss for 50% barrel. Not bad!

Its been awhile but was right at 2300 with factory 150 winchester ammo not much over the box listed speed . We use 1 in 10 twist barrels not sure how that affects things but they are tack drivers great groups to 350 yards.

Dang, where'd you get a 1:10? My faxon is 1:16, which is fine for normal loads, but 1:10 sounds like fun for launching stupid heavy cast bullets subsonic.

I get blanks from Xcaliber but a customer bought a blank from Shilen also.
This is a Ruger No1 being rebarreled from 450 to 350 haven't installed the rail yet and going to flute the barrel.
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Guessing on that charge ladder of h110 you're going supersonic?

How heavy do you think you can make a 350? Or how long of a bullet (read: stupid big hollow point for auger-size holes)?

Am I the only one that seats bullets immediately after charging cases? Whether I just drop them or weigh individually, they get a bullet right after.

After the third time in one session I had to clean up almost 40gr of powder, I got pissed and started doing it this way.

Yes you need the deep blocks that take out all the case wiggle like MTM's .