9mm KEYHOLE problem

[SawmillJack]

I loaded up my first cast loads for 9mm recently and tried them out the range at 10 yards. First I used my Kahr CW9 and after looking at the results I thought ,Heck this gun must not shoot cast." So I tried an FEG PM9R same story, likewise my HiPoint carbine.
So the problem ain't the gun must be the ammo. I bought Crown Bullet companies 125 gr LRN with 4.0 gr of Tite Group and Federal small pistol primers. Anybody ever experience this problem with 9mm. What did I do wrong?

[Ed_Shot]

What is the diameter of your the boolit when you load it in the case?

[Ed_Shot]

Sorry for the extra post.

You did not say if you had any leading issues.

I'm not familure with the boolit and I don't use Titegroup but your load is very near the top end of the scale according to Lyman 4th Ed. You might try 3.5 gr.

[SawmillJack]

Sorry for the extra post.

You did not say if you had any leading issues.

I'm not familure with the boolit and I don't use Titegroup but your load is very near the top end of the scale according to Lyman 4th Ed. You might try 3.5 gr.

.356 is the diameter of the boolits. I didn't actually observe any leading , maybe a tiny bit but of no real consequence.

[HATCH]

Web says they are .356 in diameter

You need to slug the barrel.

[Ed_Shot]

An easy comparison test would be to try some boolits sized to .358. I have .356, .357 and .358 sizing dies for my Lyman 450 and I've never slugged a bore. Got tired of changing dies and found that my CZ, G22 w/LW barrel, BHP and 995 all liked .358 just as much as much as my Ruger SS and Marlin.

[SawmillJack]

An easy comparison test would be to try some boolits sized to .358. I have .356, .357 and .358 sizing dies for my Lyman 450 and I've never slugged a bore. Got tired of changing dies and found that my CZ, G22 w/LW barrel, BHP and 995 all liked .358 just as much as much as my Ruger SS and Marlin.

I'm fairly new to casting my own and don't have any 9mm molds yet, I concentrated on .45, .44 and .357. As cheap as 9mm has historically been it didn't make any sense to me to reload for it. I bought a set of dies after the present shortage started but at that time I couldn't find any molds that were not selling for more than they were worth. I think now maybe they are more readily available. I would rather spend my time casting big bore handgun and .30 rifle projectiles though. Is there any cast manufacturers selling 9mm bullets over .356? It looks like they all set up for one diameter and don't worry about it. Will .357 semi-wadcutters shoot in the 9mm?

[detox]

Sounds like your boolits are undersized. Try .001"-.002" over (.357-.358). Montana Bullet Works can help you with samples. Just give them a call.

[detox]

From Lyman #4 Cast Bullet handbook: Pistol barrels with rifling that feature rounded edges rather than traditional square cut grooves may give poor results with cast bullets. Glock is the most commenly encountered pistol with this type of rifling.

[Reverend Al]

We were just up at our local range today and I helped a friend of ours to slug the bore of her CZ 75 9mm since she is in the process of buying a Dillon 550 and will be starting to reload for IPSC practice shortly. No surprise to me when it slugged out at .357" ... I've slugged a number of CZ 75's over the years and they usually tend to run on the large side. They all seem to shoot well even with undersized jacketed bullets (.355" to .356"), but if you try shooting a .356" or smaller lead bullet they typically "keyhole" even at short range. A .357" to .358" bullet of nearly any weight (124 to 147 grain) always seems to do the trick and then they shoot very well! So far in the guns we've tried to date there hasn't been any problem chambering the loaded cases with the larger sized bullets, but maybe we've just been lucky and have had guns with fairly generous chambers? Just my observation ...


An easy comparison test would be to try some boolits sized to .358. I have .356, .357 and .358 sizing dies for my Lyman 450 and I've never slugged a bore. Got tired of changing dies and found that my CZ, G22 w/LW barrel, BHP and 995 all liked .358 just as much as much as my Ruger SS and Marlin.

[robertbank]

.356 is on the small side for 9MM cast boolits. I size all my 9MM boolits .357. When I size boolits .356 they almost invariably start to tumble with some leading in evidence.

While not likely the case a very slow twist rate will also cause the same problem but more so with heavier 147 gr boolits. MY M&P's have 1 - 18 twist rates and won't shoot 147 gr boolits worth a darn. The will tumble at 7 yards! S&W is now making the gun with a more normal 1 - 10 twist. This should solve the problem for those who wish to shoot heavier boolits in ther 9mm guns.

Take Care

Bob

[bcp477]

Your Kahr CW9 has conventional rifling, NOT polygonal. Kahr does not use polygonal rifling on the "cheaper" models. My CM9 is the same. Further, the twist rate on the conventional Kahr barrels (9mm) is supposed to be 1 in 10".

Conventional wisdom would indicate that your boolits are undersized for the barrel, if a keyholing problem exists. So, do slug your barrel and find out.

9mm Para barrels are supposed to be 0.355" (groove diameter). Many aren't.

I am wrestling with a leading problem with my CM9. Regardless of the leading, the little pistol is consistently accurate - VERY accurate. I slugged the barrel - and it's actually undersized. It measures somewhere between 0.354" and 0.355" (groove diameter).

I did notice that the surfaces in my CM9 barrel do seem rather rough, so that might have something to do with the leading.

However, You say that you are getting no leading - but keyholing. That doesn't really make sense, unless perhaps your barrel is WAY oversized for the boolits.

In any case, there is no reason that the conventionally - rifled Kahr barrels shouldn't shoot cast well....with the right combination.

[SawmillJack]

Your Kahr CW9 has conventional rifling, NOT polygonal. Kahr does not use polygonal rifling on the "cheaper" models. My CM9 is the same. Further, the twist rate on the conventional Kahr barrels (9mm) is supposed to be 1 in 10".

Conventional wisdom would indicate that your boolits are undersized for the barrel, if a keyholing problem exists. So, do slug your barrel and find out.

9mm Para barrels are supposed to be 0.355" (groove diameter). Many aren't.

I am wrestling with a leading problem with my CM9. Regardless of the leading, the little pistol is consistently accurate - VERY accurate. I slugged the barrel - and it's actually undersized. It measures somewhere between 0.354" and 0.355" (groove diameter).

I did notice that the surfaces in my CM9 barrel do seem rather rough, so that might have something to do with the leading.

However, You say that you are getting no leading - but keyholing. That doesn't really make sense, unless perhaps your barrel is WAY oversized for the boolits.

In any case, there is no reason that the conventionally - rifled Kahr barrels shouldn't shoot cast well....with the right combination.

I have to agree with you about the accuracy of the Kahr pistols. Mine is scary accurate to the point of being accused of lying about it. "Ain't no belly gun shoots that good." I just finished cleaning it about a half hour ago, there was NO leading, the barrel is squeaky clean. Besides the key holing also happened with two other guns. I'm going to slug the barrel as soon as I can. Meanwhile I'm going to reduce the powder charge as was recommended earlier in this thread. I was doing some reading, and I can't remember where, but the guy said a lot of people have trouble reloading for the 9mm. He went on to say that cast amplified the problems and that usually the problem turns out to be too high of a powder charge. I guess we'll find out sooner or later. Out of curiosity what loading data are you using?

[robertbank]

SawmillJack if the twist rate is 1 - 10 then your problem is most likely undersized boolits. Like I said earlier I have shot 356 sized lead boolits out of several of my 9MM guns all with the same result...keyholing. I don't recall leading ever to be an issue. Look for boolits sized .357 or get into casting and cast and either shoot them unsized as they come from the mold or size them .357 and if they will chamber .358

Take Care

Bob

[bcp477]

Jack,

I use a variety of loads. For the Kahr, it seems to like everything I've fed it. The loads I've tried are as follows :

125 gr. TC boolit/ BHN 12-15....sized 0.356"/ 0.357"/ 0.358" ....over 3.7 gr. of Bullseye.

SAME boolits.....over 3.5 gr. of Bullseye.

SAME boolits.....over 3.2 gr. of Bullseye.

SAME boolits.....over 3.5 and 3.2 gr. of WST.

I have also used my "standard" SD load : 125 J-word HP....over 4.8 gr. of HP-38.

ALL of these loads have been very accurate. All of them (except the j-word HP load) seem to lead the barrel, though the amount varies. The amount of leading has decreased a bit, over time. This may support my current theory that the main reason for the leading in my CM9 is a rough bore. (The inside of the barrel under even 4X magnification shows lots of streaking - which is quite absent from my other 9mm barrels, an S&W (3rd gen.) and a Beretta. Both of those pistols, by the way, have 0.355" barrels....and do just fine with 0.356" boolits.

Another load that my other (larger) 9mm pistols seem to love is the (same) 125 gr. boolits over 4.0 gr. of HP-38. That is probably the most accurate load I've used in my other 9mm pistols.

As I said before, my CM9 barrel is smaller than 0.355". So, I probably have NO need to shoot boolits larger than 0.356". Probably. I will leave that open for now.

This weekend, I will try (the same boolits, 0.356" size)....with 3.7 and 4.0 gr. of HP-38.

As for difficulty with cast in 9mm's.....I can say that I've had it very easy, until the Kahr. For every other 9mm I've tried it has been quite easy to find good loads with cast boolits. These include 1 Beretta, 1 Sig Sauer and 3 S&W's (3rd gen.). All have had barrels at or near 0.355" (and all have done just fine with 0.356" dia. boolits). The Kahr is the first to give me "trouble"....but it is trouble I can live with easily. Since the CM9 is so darned accurate (and seems dead nuts reliable now), even with a leaded barrel....I can definitely live with the leading, even if I never fully solve the issue.

Best of luck on your problem. Do slug that barrel as soon as you can. Let us know what you find.

[SawmillJack]

SawmillJack if the twist rate is 1 - 10 then your problem is most likely undersized boolits. Like I said earlier I have shot 356 sized lead boolits out of several of my 9MM guns all with the same result...keyholing. I don't recall leading ever to be an issue. Look for boolits sized .357 or get into casting and cast and either shoot them unsized as they come from the mold or size them .357 and if they will chamber .358

Take Care

Bob


Jack,

I use a variety of loads. For the Kahr, it seems to like everything I've fed it. The loads I've tried are as follows :

125 gr. TC boolit/ BHN 12-15....sized 0.356"/ 0.357"/ 0.358" ....over 3.7 gr. of Bullseye.

SAME boolits.....over 3.5 gr. of Bullseye.

SAME boolits.....over 3.2 gr. of Bullseye.

SAME boolits.....over 3.5 and 3.2 gr. of WST.

I have also used my "standard" SD load : 125 J-word HP....over 4.8 gr. of HP-38.

ALL of these loads have been very accurate. All of them (except the j-word HP load) seem to lead the barrel, though the amount varies. The amount of leading has decreased a bit, over time. This may support my current theory that the main reason for the leading in my CM9 is a rough bore. (The inside of the barrel under even 4X magnification shows lots of streaking - which is quite absent from my other 9mm barrels, an S&W (3rd gen.) and a Beretta. Both of those pistols, by the way, have 0.355" barrels....and do just fine with 0.356" boolits.

Another load that my other (larger) 9mm pistols seem to love is the (same) 125 gr. boolits over 4.0 gr. of HP-38. That is probably the most accurate load I've used in my other 9mm pistols.

As I said before, my CM9 barrel is smaller than 0.355". So, I probably have NO need to shoot boolits larger than 0.356". Probably. I will leave that open for now.

This weekend, I will try (the same boolits, 0.356" size)....with 3.7 and 4.0 gr. of HP-38.

As for difficulty with cast in 9mm's.....I can say that I've had it very easy, until the Kahr. For every other 9mm I've tried it has been quite easy to find good loads with cast boolits. These include 1 Beretta, 1 Sig Sauer and 3 S&W's (3rd gen.). All have had barrels at or near 0.355" (and all have done just fine with 0.356" dia. boolits). The Kahr is the first to give me "trouble"....but it is trouble I can live with easily. Since the CM9 is so darned accurate (and seems dead nuts reliable now), even with a leaded barrel....I can definitely live with the leading, even if I never fully solve the issue.

Best of luck on your problem. Do slug that barrel as soon as you can. Let us know what you find.

OK guys its 2:30 am and I can't sleep so.... I slugged my barrel. I lubed the barrel and a cast 90 gr, .380 bullet and tapped it through with a 3/8 punch on the bullet bottom. The result is a heavy .354 the same as bcp's CM9. I did not observe any roughness. I don't know how much you have shot your CM but my pistol has had close to 1500 rounds through it. I just set my powder measure up to throw a 3.2 gr charge of Tite Group and will see if that helps. I'll try it tomorrow after I sleep some. If I forgot to say so, thanks to all you guys for helping me solve this.

[bcp477]

Wow. Your barrel is smaller than 0.355", too..... yet you are getting a keyholing problem. But no leading. Not a rough bore, like mine. 0.356" diameter boolits.

Are you SURE that you are getting keyholing ? You say that it's very accurate. If so, how could it produce keyholing ?

Undersized boolits seem not to be the problem, just like with my CM9. A 1 in 10" barrel should stabilize, I would think, anything you try to put through it. I see that you are using 125 grain, just like me.

I am well and truly out of ideas......

[robertbank]

How did you measure your slug. .354 would seem to be extremely tight. That said with no leading and you experiencing key holing it just doesn't add up. Given all the parameters you have listed the gun shouldn't be doing what it is doing.

Take Care

Bob

[SawmillJack]

Sorry for the extra post.

You did not say if you had any leading issues.

I'm not familure with the boolit and I don't use Titegroup but your load is very near the top end of the scale according to Lyman 4th Ed. You might try 3.5 gr.


Wow. Your barrel is smaller than 0.355", too..... yet you are getting a keyholing problem. But no leading. Not a rough bore, like mine. 0.356" diameter boolits.

Are you SURE that you are getting keyholing ? You say that it's very accurate. If so, how could it produce keyholing ?

Undersized boolits seem not to be the problem, just like with my CM9. A 1 in 10" barrel should stabilize, I would think, anything you try to put through it. I see that you are using 125 grain, just like me.

I am well and truly out of ideas......


How did you measure your slug. .354 would seem to be extremely tight. That said with no leading and you experiencing key holing it just doesn't add up. Given all the parameters you have listed the gun shouldn't be doing what it is doing.

Take Care

Bob


Bob, I measured it more than once. Using my calipers ( I don't own a micrometer) I measured across the top of opposing groove marks , or high spots on the bullet. First along the length of the bullet and then across the width of it to make sure it was actually touching the high spot on both sides.
bcp, it is accurate, but obviously not while it's key-holing. I have until now never shot anything but jacketed ammo. The first thing I said was that "I loaded up my first cast loads for 9mm." Also the fact that three different guns had identical results led me to believe that the problem would probably be the ammo. I'm wrong a lot though and I want to learn this cast stuff, the best way to do that is look at all the possibilities. Way back early in the thread Ed Shot said it looked like the load was at the top end of the scale. I notice that bcp lists several cast loads he has used in his pistol, all of them range from 3.2 to 3.7. My load doesn't appear to be copacetic with what everybody else is shooting. I'm going to make a big adjustment down and see if that makes a difference.

[doghawg]

I had leading and keyholing with the Lee 120 TC sized to .356" .357" and .358" in a Ruger SR9c which is normally very accurate. It didn't matter what size they were...I was using my first (and last) Lee factory crimp die which was sizing the cast bullets down a couple thousandths...:mad: I now size at .357" without the FCD and problem is solved.

[bcp477]

" I have until now never shot anything but jacketed ammo. The first thing I said was that "I loaded up my first cast loads for 9mm."


Oops ! Sorry Jack, I must have missed that.

You measured your "slug" boolit more or less just as I did mine. I averaged the measurements I got, to arrive at a final number.

I concur, for what that's worth, with trying lighter loads as a next step. May as well eliminate each possibility, in turn. Bear in mind that my loads are based on estimation and some trial and error, but should not be taken as gospel.

[robertbank]

To eliminate one more variable measure the bullets you are using.

The combination you are now using doesn't seem to me to be a recipe for keyholing. The latter is usually caused by not enough rotation of the bullet to stabilize it caused by either a to slow twist rate or the bullet not taking the rifling due to being to soft and driven to fast or to small in diameter. I am at a loss.

Take Care

Bob

[Virginia John]

I have experienced this a time or two and a reduced powder load usually solved the problem. Slow the bullet down and see if it stabilizes. Changing loads is the cheapest and easiest thing you can do.

[HeavyMetal]

I am going to agree with you, if keyholing was just in one gun I'd think check the muzzle but with it doing it in three seperate guns I'm thinking ammo or the loading process itself.

Lets ask a few questions:

Are you using a Lee die set? If so are you using the FCD die that comes with it?

I will suggest you take a round or two of your loaded ammo and pull the boolits and measure them. The possibility exists that during the seating operation your undersizing the boolits, this could be caused by a Lee FCD die or any Taper crimp die you may be using that is over adjusted.

Many shooter that have loaded for revolver rounds, like the 38 special, think they must be able to see a crimp! Unfortunately with a Taper crimp if you can see it is way to heavy!

Suggest you look at your die set up particularly the seating crimp die. If your using a single die to do both I wil suggest you change up and seat all your boolits and then readjust your die to taper crimp as a seperate operation.

I'm thinking you'll find your problem in the die set up.

[seanhagerty]

I am going to agree with you, if keyholing was just in one gun I'd think check the muzzle but with it doing it in three seperate guns I'm thinking ammo or the loading process itself.

Lets ask a few questions:

Are you using a Lee die set? If so are you using the FCD die that comes with it?

I will suggest you take a round or two of your loaded ammo and pull the boolits and measure them. The possibility exists that during the seating operation your undersizing the boolits, this could be caused by a Lee FCD die or any Taper crimp die you may be using that is over adjusted.

Many shooter that have loaded for revolver rounds, like the 38 special, think they must be able to see a crimp! Unfortunately with a Taper crimp if you can see it is way to heavy!

Suggest you look at your die set up particularly the seating crimp die. If your using a single die to do both I wil suggest you change up and seat all your boolits and then readjust your die to taper crimp as a seperate operation.

I'm thinking you'll find your problem in the die set up.

I think this is the answer. Pull boolits and measure them to see if you crimp die is doing bad things to your boolit diameter.

[skeettx]

SawmillJack
Been thinking about the issue
Do you use a final crimp die?
What is the case diameter with the bullet seated by the seating die?
What is the case diameter after use of the final crimp die?
Mike

wrote this and then saw the post above and had to smile :)

[SawmillJack]

[QUOTE=robertbank;2372337]To eliminate one more variable measure the bullets you are using.

The combination you are now using doesn't seem to me to be a recipe for keyholing. The latter is usually caused by not enough rotation of the bullet to stabilize it caused by either a to slow twist rate or the bullet not taking the rifling due to being to soft and driven to fast or to small in diameter. I am at a loss.

Take Care

Bob


I have experienced this a time or two and a reduced powder load usually solved the problem. Slow the bullet down and see if it stabilizes. Changing loads is the cheapest and easiest thing you can do.


I am going to agree with you, if keyholing was just in one gun I'd think check the muzzle but with it doing it in three seperate guns I'm thinking ammo or the loading process itself.

Lets ask a few questions:

Are you using a Lee die set? If so are you using the FCD die that comes with it?

I will suggest you take a round or two of your loaded ammo and pull the boolits and measure them. The possibility exists that during the seating operation your undersizing the boolits, this could be caused by a Lee FCD die or any Taper crimp die you may be using that is over adjusted.

Many shooter that have loaded for revolver rounds, like the 38 special, think they must be able to see a crimp! Unfortunately with a Taper crimp if you can see it is way to heavy!

Suggest you look at your die set up particularly the seating crimp die. If your using a single die to do both I wil suggest you change up and seat all your boolits and then readjust your die to taper crimp as a seperate operation.

I'm thinking you'll find your problem in the die set up.


I think this is the answer. Pull boolits and measure them to see if you crimp die is doing bad things to your boolit diameter.


SawmillJack
Been thinking about the issue
Do you use a final crimp die?
What is the case diameter with the bullet seated by the seating die?
What is the case diameter after use of the final crimp die?
Mike

wrote this and then saw the post above and had to smile :)

Sorry guys for taking so long to get back but life interfered with the fun stuff for a few days. I loaded up some cast rounds though, starting at 3.2 and working my way up to 3.8 grains of TiteGroup and the first problem I ran into was that the Lee adjustable charge bar wouldn't go that low. So I tried the disc and it also threw very erratic loads. Even tapping rather hard on the powder canister before each load didn't help. So I ordered the Lee “Perfect Measure”. Finally I'm getting fairly accurate measurement.

As far as the FCD my 9mm set thankfully doesn't have one. I'm sorry I ever saw the one I own in .45 acp. I discarded all rounds loaded before I got the new powder measure. Today I finally got to the range to try them. No loads below 3.5gr would reliably cycle the gun but they did not key hole. 3.5gr worked like a charm and was fairly accurate. 3.7 and the keyhole problem returned. I also tried Winchester 230 with similar results. I think the problem is solved. I thank everyone who chimed in and offered help. Even if the advice didn't solve the problem, it gave me valuable insight on things I should be checking if I ever have a similar problem again

I also loaded some Berry's 215gr copper coated with the original load that started this mess, 4gr of TiteGroup. This turned out to be a pretty accurate load in my CW9.