Needing to seat deeper to pass the plunk test in barrel with PC

[Thomas918]

I need to seat my PC bullets .020 deeper to pass the plunk test. The round doesn't rotate freely but seats flush and chambers fine. Now I'm not against doing this but I want to seat at 1.135(currently having to seat 1.120ish to pass the plunk test) for 9mm 147 FN round to lower pressure since I'm using a fast powder. Is it safe to seat the bullet at a longer length even though it doesn't rotate freely? Ive always heard it increased pressures but I'm thinking it would increase the pressure as much as a deeper seating depth.

[kungfustyle]

If you change anything, it changes everything, Start over on working up a load. Yes that will increase pressure. I'd start back at the minimum load and work back up.

[Grayone]

I need to seat my PC bullets .020 deeper to pass the plunk test. The round doesn't rotate freely but seats flush and chambers fine. Now I'm not against doing this but I want to seat at 1.135(currently having to seat 1.120ish to pass the plunk test) for 9mm 147 FN round to lower pressure since I'm using a fast powder. Is it safe to seat the bullet at a longer length even though it doesn't rotate freely? Ive always heard it increased pressures but I'm thinking it would increase the pressure as much as a deeper seating depth.

I believe you would have to start over with the reload data. A plus side would be that you would be using slightly less powder for the same velocity and pressure. Powder coat to me also a cleaner gun and no leading even with a softer alloy.

[243winxb]

A smaller bullet diameter may fix the chambering problem. Size the bullets to be a bit smaller then the throat.

My 9mm throat measure .3568" Bullets larger then this need to be seated deeper, shorter COL.

https://www.thehighroad.org/index.ph...9mm-luger.317/
See Photos at link.

[poppy42]

I have a few questions. Is this a Max powder charge? Are you approaching maximum pressure allowed with this powder charge? You say it passes the punk test but doesn’t turn freely could you elaborate on this? have you actually fired any of these rounds with the COL of 1.135? In conclusion the first thing I wanna say is COL is meant to be a guide and not an absolute. You’re talking about decreasing the col by .015. (1.135-1.120=.015) That’s not a heck of a lot and could be less or equal to the thickness of the pc and could certainly be within the variation of one round to the next. (deformation of a soft pointed or soft lead bullet ) I seriously doubt decreasing the combined overall length of the cartridge by 0.015 would increase pressures to dangerous levels! Unless you’re already pushing the envelope! If it was me I’d load a few and shoot them.

[charlie b]

A smaller bullet diameter may fix the chambering problem. Size the bullets to be a bit smaller then the throat.

My 9mm throat measure .3568" Bullets larger then this need to be seated deeper, shorter COL.

I wish I could. My 9mm has no throat. Until I get that fixed I will continue to shoot jacketed in it.

[243winxb]

I wish I could. My 9mm has no throat. Until I get that fixed I will continue to shoot jacketed in it.

Mine measures .017" almost none on this Taurus G3C.

https://www.thehighroad.org/index.ph...3c.4003/#media

[DougGuy]

Have the barrel(s) throated. Simple as that.

It is dangerous to seat deeper, unless you are right on top of the load data and know you are in a safe zone with the shorter COA and a reduced powder charge.

It is even MORE dangerous to run the gun with the slide cramming the boolit into the rifling as this can cause boolit setback, and this is just like seating deeper and not dropping the charge weight.

9mm Luger is a high pressure round, 35,000psi and it has a quite small case capacity when assembled, boolit setback as little as .010" can send pressures skyrocketing.

What guns what models are we discussing here?

[Thomas918]

I have a few questions. Is this a Max powder charge? Are you approaching maximum pressure allowed with this powder charge? You say it passes the punk test but doesn’t turn freely could you elaborate on this? have you actually fired any of these rounds with the COL of 1.135? In conclusion the first thing I wanna say is COL is meant to be a guide and not an absolute. You’re talking about decreasing the col by .015. (1.135-1.120=.015) That’s not a heck of a lot and could be less or equal to the thickness of the pc and could certainly be within the variation of one round to the next. (deformation of a soft pointed or soft lead bullet ) I seriously doubt decreasing the combined overall length of the cartridge by 0.015 would increase pressures to dangerous levels! Unless you’re already pushing the envelope! If it was me I’d load a few and shoot them.

I have a Canik Rival. My go to load has been 3.5gr n320 with Xtreme copper plated at 1.150. Their projectile is .670 and my flat nose cast powder coated are .630 to .640 which is another reason I'm not enjoying powder coating. My Hitek coated are .625 consistently. So even having my road loaded 3.1gr n320 at 1.120 isn't that much of a difference due to projectile length; it still bothers me.

[Thomas918]

What guns what models are we discussing here?

I have a Canik Rival

[ioon44]

I am using a Hi-tek coated 140gr FP in a new Walther PDP and I had to seat to 1.015" to pass the plunk test, I had been seating to 1.025" with my Walther PPQ SF.

I dropped the charge from 3.2 gr to 3.0 gr and got the same chronograph readings, so .010"can make a difference.

[Castinator]

I've had a similar problem with certain boolits and autos, a good reason not to double coat. And a good reason not to load 100%+. And to use a good strong taper crimp to prevent setback.