Loading subs for 16" barrel?

[HawgBonz]

I'm in the process of working up a 147gr sub load for the FPC and I'm havin some grief with XTP/truncated cone type projectiles.
When loaded to the seating spec of 1.1" on the Hodgdon site I get stuck cartridges when manually cycling for a fit check. I blackened the XTP and found
that it was making contact at the base line/bearing surface junction. Made a "loose case" and seated it in the chamber to 1.080 OAL. Dropped the charge to minimum
and tried them at that depth with reasonable success far as I can tell. Although both factory and reloads have "pooched out" primers.
..Went to look up some loads for a coupla boxes of 147gr GDs figgering Speer will have some good data.
And there's this warning about "147gr not recommended for barrels over 10 inches". Huh? 😵
Anybody ever heard of that? I know certain length bullets won't stabilize in certain twists.
But I haven't heard of bullets just not being "recommended".. Am I havin a senior moment or izzat a lawyer talkin?

Anyways, the one box of factory 147gr Fiochi ammo I currently have does fine. Got 4 more varieties inbound to try.
All of it does just fine in some of my other 9s.
Handloads, Factory loads, Golf Cart Lab.

 

[BrettB]

I’ve run thousands of 147 gr 9mm through a 16” barreled Ruger PC carbine and Kalashnikov KR9
Have you dropped bullets in a chamber checker or plunk test in the barrel
Have you tried a different projectile ?
Pretty sure any load a 147 gr 9mm will be subsonic.

 

[Timfoilhat]

@HawgBonz you using a chronograph? Do you have one?

 

[HawgBonz]

Have you dropped bullets in a chamber checker or plunk test in the barrel Yep
Have you tried a different projectile ? Yep
Pretty sure any load a 147 gr 9mm will be subsonic. Unless ya have a really short throat, like the FPC apparently has. 🥴

you using a chronograph? Do you have one?

Generally with subs I'll start way low and work up till I start crackin. All while checkin brass for pressure signs.
Once I'm in the ballpark I'll tweak it using the chrony so it's not edgin so close that it changes with the seasons..

 

[georgel]

Could the warning on long barrels be because they can get "stuck" with lower charge loads? At 10" I believe you've reached the limit on case capacity to generate more pressure.

I have to load truncated cone bullets shorter and I think I'm at about that 1.08". Remember, the shorter seating is reducing powder space/capacity and increasing pressure. I think my loads are almost touching the powder.

 

[HawgBonz]

Could the warning on long barrels be because they can get "stuck" with lower charge loads? At 10" I believe you've reached the limit on case capacity to generate more pressure.
I have to load truncated cone bullets shorter and I think I'm at about that 1.08". Remember, the shorter seating is reducing powder space/capacity and increasing pressure. I think my loads are almost touching the powder.

Yer guess is good as mine on that 10" thing.. I haven't seen any talk of that anywhere else so far.
Been dropping charges in line with the OALs. The loads I was tryin today were mainly WSF. Also tried a dash of Titegroup and that worked ok.
But I'm kinda thinkin I'll dink with some slower powders tomorrow. Got some Silhouette, HS-6 and AA#5.
And it may be that the smarter move is to just ditch the XTP's for this gun. My old Everglades 147 JHP loads worked fine.
None of the other 9s are nearly so particular. The P365 loved the XTPs.

 

[92G]

its a blowback action so the longer the projectile stays in barrel the higher the pressure as the breach opens. a 147 gr bullet will spend more time in the barrel. the warning about bullet weight is likely related to the blowback action.

for subsonic loads theres tons of pretty standard load data out there. ive used titegroup to load 147 and 165 gr x-treme bullets. the 165’s are dicy and probably not the safest load if one is sloppy with their charge weights. they only cycle hammer fired pistols like my P-09 or USP. they will not cycle anything w a stiff recoil spring like striker pistols. the 165 also will only work w certain brass. thick brass will bulge and get stuck in chambers. despite all the extra work, the 165’s are retarded quiet.

ive not loaded XTP for 9mm just 357 sig so cant comment on your seating issue. does the FPC just have a short throat?

 

[HawgBonz]

ive not loaded XTP for 9mm just 357 sig so cant comment on your seating issue. does the FPC just have a short throat?

That's what it seems like. The XTP ammo I'm making works fine in the other 9s I've tried them in and OAL is by the manual.

 

[92G]

Btw those spent primers look ok to me. Maybe I’m missing something?

in terms of OAL issue perhaps a RN profile will allow more OAL flexibility. XTP’s are rather pricy so i prioritize them for high velocity loads in 357 sig. They‘d probably be perfect for 9x25 as well.

 

[HawgBonz]

Btw those spent primers look ok to me. Maybe I’m missing something?

The factory brass looked pretty normal with very mild cratering. The one reload primer is pierced and the others are weirdly "pooched out".
That may come from a combination of the weakened metal around the primer strike and the longer dwell for the blowback.
They just look kinda strange to me.

Have you dropped bullets in a chamber checker or plunk test in the barrel

Ordered in a chamber checker and apparently the loads are well within spec.. Tried the plunk n spin gig with all the ammo I have on hand.
Of all that ammo only my 147gr XTP loads won't plunk or spin freely in the chamber of the FPC.
And FWIW I tried the same thing with by-the-manual GD 147HP and they wouldn't pass, either.. 🤷‍♂️