9mm keyhole

[wolfdog]

Good morning,
Went to the range yesterday to shoot some cast semi auto rounds. Everything was going fairly well till I took my 9mm to distance. 15-20 yards I was having pretty good success. Wandered our to 37 yards and had the vast majority of rounds hitting sideways. Bullet is a 120grn lee TC, air cooled WWs, tumble lubed in lee liquid alox mixed with mineral spirits. Gun is a canik TP9 SFX with the 5.2" bbl and load is 4.0grns of titegroup. I'm guessing this is giving me just over 1100fps and I'm coming out of super sonic? I'm considering a max charge of Win 572 which should put me at 1200+fps with the same bullet and keep me super sonic for a bit longer? Load will be carried for trail walks and camper duty as it's light and has a ton of ammo on board so shouldn't need much backup.

[LenH]

Check the Cast boolit thread there is thread about Keyholing Won't stop. Your answere will be in that thread.

[Screwbolts]

I would think , undersized boolitz. OP, did you notice the thread in Cast Boolits section of this forum discussing the very same thingy.

What ya huntin with them keyhole boolits?

[wolfdog]

I didn't check the other section, I doubt undersized as I'm getting no leading. If I can work things out, I should be able to push a 120ish grain bullet to 1200+fps and I have some spots that allow for 30 yard shots..so there is a possibility of hunting with said setup.

[Thumbcocker]

In my experience the Lee 125 fp shoots better than the tc. I would advise you to look at the keyhole thread.

[wolfdog]

On my way there now, also looked at another forum/post and they are having the exact same issue with the exact same gun/bullet combo. Undersized seems to be the key in that thread, .358 bullets suggested. After reading, if that's the case, I'm going to try to powder coat said bullet first, if not..looks like a new mold is in order..

[wolfdog]

Looks like undersized bullets seem to be the theory there too. T went to my reloading room and grabbed a loose bullet to measure. Noticed they had lube in the lube groove. Which is odd as I don't have anything to do that. I either tumble lube or PC. They were measuring right on .356. I remember I got a bunch of bullets from a guy here who gave me some TCs and some .357 RNFPs for my 9mm. I am thinking maybe he sized them. I cast a bunch of new bullets and checked, I'm right on .358. PCed them and loaded them up. No keyholes, No keyholes with the .358rnfps either. So it looks like I just had a bunch of under sized bullets. I'm going to start working up a load with 572 as I hear TG doesn't always play well with cast either.

[dverna]

9mm cases can swage a cast bullet down if not expanded enough. Pull a bullet and check it. I use "hardball" alloy so I get less swaging than using a softer alloy. If sizing to .358' does not work, try shooting as cast.

There is no discernable difference in accuracy going transonic in a pistol bullet at those ranges.

[wolfdog]

9mm cases can swage a cast bullet down if not expanded enough. Pull a bullet and check it. I use "hardball" alloy so I get less swaging than using a softer alloy. If sizing to .358' does not work, try shooting as cast.

There is no discernable difference in accuracy going transonic in a pistol bullet at those ranges.

I was thinking I may be coming out of supersonic around 40 ish yards, but reading the thread, undersized bullets seem more likely. I'm shooting as cast, I had forgotten someone gave me a bunch of them to try. I'm also shooting clip on WW. So they are a bit tougher. I'm going really light on the crimp as well, just enough to take the bell out of the case. Things went far better today, none of my rounds hit the target sideways, however, the original load still did it. I'm fairly certain the person who sent me them sized them. I will check my email, it was a long conversation, but I think he did tell me one group was sized.

[gloob]

That's a new one to me, having non-GC/PC cast bullets tumble without leaving any fouling. Just when you think you have things figured out.

"Noticed they had lube in the lube groove. Which is odd as I don't have anything to do that."

You probably do, though. Lots of folks assume lube grooves don't matter when using tumble lube, and that a grooveless bullet would be the same as a grooved one. But if you coat the bullet with lube and then run the bullets through a sizing die, you might see this effect. That the lube gets completely cleaned off the bearing surfaces. But some of it gets picked up by the lube grooves, and the grooves can even get completely filled. I would imagine that the same thing happens when you fire an unsized TL'd bullet.

You can also fill in the small grooves on a TL bullet with lube, if you tumble them in a single layer in a smooth flat pan.

[deltaenterprizes]

When I was a commercial bullet caster I had quite a few people that were having problems with 9mm 125gr boolits tumbling.
Contrary to what members here suggest a well known pistol barrel maker , Irv Stone of Bar-Sto barrels informed my customer that the problem is the twist rate of the barrel.
Import barrels are 1:9, 1:10 domestic barrels are 1:16 like a 38 barrel.
A 147gr bullet with more surface area on the driving bands will solve that problem.

[quilbilly]

In my experience the Lee 125 fp shoots better than the tc. I would advise you to look at the keyhole thread.

I 100% agree. I have a T/C carbine in 9mm and had an awful time with key holing (among other things) until I switched to that Lee 125 RF sized to 358 and then quite trying to turn the 9mm into a mini-357 mag. The carbine loves an mv of about 1150 using either Bullseye or Unique and is now "minute of pop can" out to 120 yards with iron sights. It speaks with authority and a satisfying thump on coyotes out to 150 yards. Ballistically, at 125 yards that carbine is similar at 125 yards to a 38 sp at 25 yards from my revolver.
It took a while but I learned not to ask the cartridge to be something it isn't meant to be.

[wolfdog]

That's a new one to me, having non-GC/PC cast bullets tumble without leaving any fouling. Just when you think you have things figured out.

"Noticed they had lube in the lube groove. Which is odd as I don't have anything to do that."

You probably do, though. Lots of folks assume lube grooves don't matter when using tumble lube, and that a grooveless bullet would be the same as a grooved one. But if you coat the bullet with lube and then run the bullets through a sizing die, you might see this effect. That the lube gets completely cleaned off the bearing surfaces. But some of it gets picked up by the lube grooves, and the grooves can even get completely filled. I would imagine that the same thing happens when you fire an unsized TL'd bullet.

You can also fill in the small grooves on a TL bullet with lube, if you tumble them in a single layer in a smooth flat pan.

This is a non-TL bullet design and other than for my GC 35rem bullets I don't have a sizer. Also, I use LLA which is dark brown and this is white. Lastly, remember the gentleman sending me the bag of bullets and me loading a bunch, and setting them aside. I has always fired them from a Hellcat with a 3" bbl at 10 yards and under, so never worried about performance at range. Now that I have the Canik I was stretching it's legs a little bit. I had only fired about 5 rounds in the barrel when I noticed the tumbling then stopped to figure it out. Yesterday I was trying to empty the brass a bit and got pretty good leading at that point (probably 100 rounds instead of 5). I will PC them and see what they do today. But if not, I may have to switch bullet molds. The 125 seems an option but is there anything heavier in a .358 diam. by lee I could consider?

[wolfdog]

I 100% agree. I have a T/C carbine in 9mm and had an awful time with key holing (among other things) until I switched to that Lee 125 RF sized to 358 and then quite trying to turn the 9mm into a mini-357 mag. The carbine loves an mv of about 1150 using either Bullseye or Unique and is now "minute of pop can" out to 120 yards with iron sights. It speaks with authority and a satisfying thump on coyotes out to 150 yards. Ballistically, at 125 yards that carbine is similar at 125 yards to a 38 sp at 25 yards from my revolver.
It took a while but I learned not to ask the cartridge to be something it isn't meant to be.

There is a load with 572 and a 124grn bullet breaking 1200fps...mini 357mag indeed . There is a load for 160grn bullets on Hodgdon's website. But man those 158grn .358s don't leave a lot of room for powder..I would want to do a bit more research before trying it. Still 158grn bullet at 900 fps seems nice...

[wolfdog]

When I was a commercial bullet caster I had quite a few people that were having problems with 9mm 125gr boolits tumbling.
Contrary to what members here suggest a well known pistol barrel maker , Irv Stone of Bar-Sto barrels informed my customer that the problem is the twist rate of the barrel.
Import barrels are 1:9, 1:10 domestic barrels are 1:16 like a 38 barrel.
A 147gr bullet with more surface area on the driving bands will solve that problem.

So I could be having more than one issue, outstanding. Lol, well, more chances to empty brass at the range, can't complain.

[gloob]

^To throw a monkey wrench into this, all of my 9mm's have a twist rate of about 1:9 to 1:10, including original Glock 9mm barrels and aftermarket 9mm barrels made in the USA. They shoot 124 TL bullets just fine, even with soft, unquenched bullets.

The idea that twist rate causes fouling or keyholing (b/c of the bullet "tearing out" or "skidding") are possibly off base. I have seen the 9mm twist rate villianized for being too fast in many guns, and that harder bullets are required compared to other calibers of similar pressure/velocity. But harder bullets also reduce another major issue with 9mm, which causes fouling and keyholing. Case-swaging.

As far as keyholing due to too fast a twist rate, I don't believe a twist rate can be too fast (to stabilize... it might explode or "skid" if you went crazy high). A bullet that spins faster than needed will still be stable. It's when the twist rate is too low for the bullet that it keyholes.

[wolfdog]

Shot some 120grn TC, PC bullets today with 572. had about a 2" group at 10 yards. Some of the bullets are hitting the rifling just a bit if they are PCed but the TL bullets do not. So I plan to set the PC bullets back just a bit. Tried some 158grn 357mag bullets as well. Accuracy was good, but they ram directly into the feed ramp about 10% of the time. Also tried some 125grn .358s that were sent to me sized to .358 and they worked ok, but were low left compared to the sights and my 120grn TC bullet. I'm going to shoot the 120TC as cast and see if PC vs TL makes a difference. Over all, great range day. I has 100 of the sent 120 TC bullets loaded and tried them in my Hellcat. They leaded extremely quickly. Safe to say both guns like .358 over .356. Over all, this is just a fun project and I'm enjoying the experimentation. As a side note, if anyone shoots 38-55 Win, PM me. Hodgdon just sent me some new reloading data and I can forward it, lots of new powders being used and really opens up some options.

[MT Gianni]

Dog, I'm reading that you're considering a max charge of 572 so assuming you are shooting a mid range load? You're not one to quit on things but I hate that mold in the TL style. The conventional isn't that different from the venerated 356402 which followed the original German military design. It looks like PC is changing the rifling engagement so that's a good thing.

[trapper9260]

Seat a boolit in the case and then pull it and see what it comes to , if it is under then what is needed . What I done is I have one gun that take .358 that it shoot best for it is a 9mm and needs a bigger boolit , what I done is I use the expander and seating die for 357 mag /38 spl to finish load the round and it all come to what I needed. Also you will not have to worry about swage the boolit down for what the BHN is. You can shoot what you like that way.

[gloob]

^ That would be so satisfying to see. I can't imagine how any carbide 9mm die, set per the norm of shell holder kissing or even just close proximity with the mouth of the die, would not result in at least some case swaging of any sub 22 BHN 124+ grain bullet seated anywhere close to SAAMI max, in just about any commercial 9mm case.

But when your gun shoots good enough, because you changed size or hardness, most people just tend to stop there. And I can't blame them. Took me a year or two and and over a thousand smoky, innaccurate, bore-fouling rounds before I came around and bothered to check for case swaging. And that's with a Glock. Guns with much shorter leades probably shoot slightly case swaged bullets good enough to barely notice any problem unless you're shooting really long range or off a bench rest. And if it works, it isn't really broke. But after measuring the base of a pulled 358 bullet at 352, I can't even stand the thought of not fixing that.