10mm trouble lil bit.

[jeeptim]

Hey fellas..
So been working on a load for 10mm G-20 had a lil trouble with unique come to find a good cleaning of the slide and firing pin fixed that up. But in the mean time got lots of positive feedback with long shot so I got some and loaded up as follows.
New Starline 10mm brass.
Rainer 180gr rnfp
CCI LPMP.
9gr of long shot.
Seated 1250 lil deep
Mild crimp with lee FCD
Aprox 1200fps
And keyholing.
Why would a bullet do that?
I took such care in loading.
AM I seated to deep? To much powder? To lil powder?
I have loaded 1 point 2 seven 5 bizzilan rifle rounds with very very few issues loaded a ton of colt 45 no problem. My Son is into hand guns I love hanging with my son so I am now into hand guns. Along with the G-20 I'm waiting the 10 days for my G-19 9mm.
I dislike very much buy-in loaded ammo in fact it makes me sick to think about it.
I bought a 50 rnd box of 10mm $37.00 need I say more.
So I need to get a Handel on pistol ammo 10mm, 9mm,45acp, 357/38, 44mag, for whatever reason the rimmed cartridges seem to go well any advise especially with the 10mm and key holing would be appreciated.
Thanx

 

[forty_caliber]

Keyholing is a sign that the bullet isn't stabilizing before it leaves the barrel. Too much crimp, barrel fouled with lead or copper, wrong diameter bullet, and defective bullets come to mind.

.40

 

[JT-AR-MG42]

Reads to me like the load is within spec for the caliber.
And most keyholing is a bullet/barrel problem, not powder related.
Guess I would put calipers to the bullets and slug the barrel.
Maybe take a close look at the muzzle for anything as well.

If you are sure the bullets are keyholing.
FWIW
A new cardboard backer behind the target might help to eliminate any
uneven target paper tearing that is sometimes mistaken for keyholing.

JT

 

[Dudedog]

I like and use the Lee FCD but it can resize bullets.
I would measure a couple of bullets them load a dummy round and pull that bullet.
Measure it and make sure you are not resizing the bullets.

Good advice here

A new cardboard backer behind the target might help to eliminate any
uneven target paper tearing that is sometimes mistaken for keyholing.

 

[.308 Norma]

I bought a 50 rnd box of 10mm $37.00 need I say more.

Ouch!
Not trying to be a wise guy, but are those 74 cents apiece loads keyholing too? The answer to that would tell you whether it's your gun or your loads.

 

[[email protected]]

My thoughts are that the rainer bullets are not engaging the rifling enough to stabilize. Rainer sizes their bullets the same diameter as FMJ, but they are plated bullets. You generally use lead or low end jacketed data (not 1/2 grain from max load) for plated bullets . Given your load and the rifling profile of you Glock, it's sounds that they are just too fast to stabilize. I imagine that you worked the load up from the starting load to get to where your at now, so how did the other test loads shoot? If you just picked out a load to try, which is only a 1/2 grain lower than the listed max load for a FMJ, you can be asking for more trouble than an inaccurate load. Hodgdon lists 9.5 grains as a max load for a FMJ.

So assuming that you did work the load up and the other rounds , with a lower charge weight, were also keyholing, I would say that your gun simply does not like that bullet.

Rainer sizes theirs to .400 and Berry's size theirs at .401 diameter. It isn't much difference, but understand that there is manufacturing tolerances with any mass produced product, and the ones you have may be at the smaller end of what Rainer accepts as within spec.

The following is quoted from Rainer's site "In general, our bullets typically perform their best when shot at velocities no greater than 1,200 to 1,250 Feet per second (FPS)."
From Hodgdon's site:
start load 8.5 Velocity (ft/s) 1,221
max. load 9.5 Velocity (ft/s) 1,287

 

[jeeptim]

Good info!!!
The factory ammo worked well.
The slower ammo worked well sounds like the plated bullets moving that fast are not catching the rifling.
Some fmjs are on the way.
Some years back I had some plated 7.62x39 keyhole as well moved to fmjs no more keyhole.
Thanx