9mm cast hollow point is tumbling

[landers]

I need a little help. I just got a chance to shoot some bullets from a new hollow point mold and am baffled at the results. The bullets are 115gr at 1100 fps and sized .0015 over my bore after being pulled from a loaded case. The problem is that they are tumbling or key holing at 10 feet. As you can imagine accuracy is all over the place, I suppose thats expected when bullets fly sideways. I have tried two different guns with the same results, any suggestions?

Landers

[Charlie Two Tracks]

I think it would help if you told what the powder is and the amount. I don't know how you can tell it is going 1100 fps when it tumbles at 10 ft.

[Old Caster]

I would try to go just a bit bigger and see if there is a difference. 10 feet is real close for this to happen and there aren't many things that would do this except too small of a bullet in too large of a bore. -- Bill --

[MtGun44]

Typically tumbling is caused by undersized boolits not gripping rifling.

If they are gripping the rifling, they will spin. If the spin, they will not tumble.

How are you measuring? If you are using a caliper, your measurements are very
suspect as they are +/-0.001, meaning a .002 error is possible. You need a micrometer
accurate to .0001" for this work. An affordable one (there are others, for sure) is a
Fowler from Enco Tools, which usually runs around $40.

Bill

[landers]

My brain is faster than my fingers, I thought I put in all of the load data. I am using 4.6 gr. of HP-38, I do not have a chrony so the velocity is an educated guess from the Hodgdon manual. After following the great advise on this forum i really tried to set up my 9mm reloads before shooting them. I slugged my barrel, .3552 using a micrometer not a caliper. I made a dummy round and set up the crimp so the pulled bullet was .3565 dia. which matches unloaded bullets from the sizing die. I use the same sizing die for my cast 147gr HP with great accuracy and results. If I missed anything please let me know.

Landers

[runfiverun]

back the load down to about 3.6 grs and try again.
the longer boolit has a longer bearing surface it grips the rifling better.
they could both be somewhat undersized still.
you just get away with it in the case of the longer surface.

[PS Paul]

Hmmmm. You've actually checked on a couple of things that we would immediately look to: size, slugging the bore and the possibility the boolit is being swaged dwon in the case when crimping......

So, what type of pistol AND have you shot other cast boolits in it before? Or is this the first go-round with cast in the gun?

The signs point immediately to an undersized boolit, so I would look at either shooting "as cast", presuming you are sizing them. If you are tumble-lubing, you may or may not be sizing them? If the size is still too small, there is "beagling" the mold and/or adjusting your alloy to throw a little larger diamter boolit.

Curious, I'll be checking back to see. There is a solution, but it may begin to get more complex if the variables mentioned are addressed correctly.

[landers]

PS Paul - the gun shoots my 147gr cast HP great, all of my bullets are sized in a star.

Runfiverun - I am reluctant to drop my load that low, I cant find any data showing less than 4.3gr in my manuals. I do like to experiment a little but that much is out of my comfort zone.

Thanks for all of the support here, this is my first thread due to all of successesse I have had from reading others input. I wish i knew how to do those fancy quote balloons when replying to other post. :smile:

Landers

[Dusty Bannister]

What manuals are you looking at? Do you have the Lyman Cast Bullet Handbook 3 or 4?

[williamwaco]

Typically tumbling is caused by undersized boolits not gripping rifling.

If they are gripping the rifling, they will spin. If the spin, they will not tumble.

How are you measuring? If you are using a caliper, your measurements are very
suspect as they are +/-0.001, meaning a .002 error is possible. You need a micrometer
accurate to .0001" for this work. An affordable one (there are others, for sure) is a
Fowler from Enco Tools, which usually runs around $40.

Bill



Ditto.

If you are using a caliper, forget it.

If you don't have a good mike, size them .357 or .358.

If you do have a good mike, size them .357 or .358.

Be sure they are still .357 at least after pulling a seated bullet.

You didn't mention the alloy but I bet you are casting them hard.
Hard, undersized bullets are a perfect storm for leading and tumbling.
Try something no harder than air cooled wheel weights.
I prefer BNH 10 to 11 for the 9mm.

[landers]

I am using a micrometer to measure my boolits, and the alloy I use for my HP boolits is 20-1 having a BNH 10. I read every post I could before I started casting for my 9mm and have tried to cover all of my bases from the start. My chamber is a little tight and wont chamber .358, I measured my sized boolits at .3567 from the sizer. I dont have a die in between so Im kinda out of luck with that. If this keeps up I may have a master caster mold for sale [smilie=b:
Landers


Ditto.

If you are using a caliper, forget it.

If you don't have a good mike, size them .357 or .358.

If you do have a good mike, size them .357 or .358.

Be sure they are still .357 at least after pulling a seated bullet.

You didn't mention the alloy but I bet you are casting them hard.
Hard, undersized bullets are a perfect storm for leading and tumbling.
Try something no harder than air cooled wheel weights.
I prefer BNH 10 to 11 for the 9mm.

[subsonic]

What does the boolit look like? Does it have a lot of bearing surface, or just a little?

[Shiloh]

ANy leading??

Ditto the advice on the mike. I have a Lyman made in China that measures identical to the lower end Mitutoyo i compared it with.

[landers]

Dusty Bannister - I have both books. I am not near them today but I will go back and look at them to see if I missed some load data.

Shiloh- There is no evidence of leading but I only shot 4 rounds through each gun. When each round was sideways I figured it wasn't worth wasting the primers and powder at this point, they may be the last ones I can get for awhile. Its situations like this that makes me wish I was hoarder! :smile:

Subsonic - it is a light bullet so the bearing surface is pretty short compared to the 147gr I cast, which shoots well out of both guns.

Two questions:
1.Is there a chance that a slower or faster burn rate powder may make a difference? I am using HP-38 now.
2. How much diameter difference in the bullet can make or break the bore seal? Can a difference of say .0005 make or break it or does it take a substantial difference of like .001? I am new at casting so just throwing out some ideas and questions.

Again thanks for all of the great input everyone is giving.
Landers

[Harter66]

I'm still learning here too so bear w/me.

I started a 40 recently after good success w/9s,38s,357s,45 Colts/ACPs/A Rs,32 Rem,8mm,06',7mm. The 1st thing that happened was what plunked did'nt fit in the magazine,next was feed issues w/said dummies,then through the whole load range it key holed . 2 powders,2 primers. The boolits were 403+ in the 401 bore and right at the top charges of Unique things settled down to egg shaped profiles at 20yd. The water dropped WW/1/20, 50/50 was to soft for the 40 but had worked well in the other pistols listed. ACWW didn't do it ,in that gun, I cut the WW 25% w/1/20 and water dropped ,viola', 4" standing offhand 20yd groups , round holes,and no leading.

My suggestion is to get to about a 12bhn .75/25-50/50 w/WW will keep the bullet soft enough to expand AND stay together AND stay on the rifling. I'd water drop the 75/25 if it were for me.

The other choice is to back the load down a little more or change powders from where I stand.

[Larry Gibson]

landers

As runfiverun suggests your load is to hot for the cast bullet (I don't see a mention of the alloy?) and the data you're finding appears to be for jacketed bullets. I also suggest backing off to 3.6 gr and work up to 4 gr of HP-38. I use 4 gr Bullseye as my standard "go to" load with 115 gr cast in the 9mm. Both HP-38 and Bullseye are fairly close in burn rate.

Larry Gibson

[gefiltephish]

Since everyone else pretty well covered the usual, I'm gonna toss this one in from out in left field.

Is there any chance that the barrel is fouled enough with copper to effectively create very "shallow" grooves or fill in the corners? Any chance of finding a recovered bullet to examine the engraved rifling? Was the gun acquired new or well used? Could there be copper/lead layers?

Yeah it's probably a real stretch, but food for thought anyway. I'm thinking the other guys are right about the too hot load.

[gefiltephish]

double post.

[PS Paul]

Since the gun, according to the OP, shoots the 147 gr. cast HP well, I am startin to think the lighter boolit combined with the higher velocity is causing the boolit to lose its balance in flight. Stil not sure on the make or pistol or style of rifling (a' la Glock), but it would appear a COMBINATION of factors, greater than the sum of its parts, is to blame.

I suppose we'll have to wait for the OP to regroup, reload and send us results......

[easymoney]

I had the same problem with my 9's. Sought help from this site and received several good suggestions. I don't remember who suggested it but what finally solved the problem was slowing the boolit down. Not a lot but just enough. None of my books show reduced loads for cast boolits so I started at the load I had been using, that allowed the pistol to function as required, and began backing the load down a 1/2 grain at a time. When I reached the point where the bullet stopped tumbling and the pistols still functioned properly I stopped. Surprisingly the accuracy was still within acceptable levels for my type shooting. I use cast boolits for target/plinking/combat style shooting and not home/hunting/self defense so my level of accuracy may not be up to your standards but I can't tell the difference between my cast loads and factory JHP in that department within the ranges I shoot. These guys do have the answer to your problem but it does take some experimenting and effort on your part to sort through the volumes of information they provide. Good Luck!

[Dusty Bannister]

Both HP-38 and Bullseye are fairly close in burn rate.
?
Looking at the other information in this forum archives, it appears that HP-38 and W-231 are alike and since you do have Lyman Cast Bullet Handbook, 4th ed, you will have a better idea of what your minimum suggested load data is.

I think you have pretty well concluded that your 115 grain HP cast bullet might not work, no matter what you try. Dusty

[MtGun44]

Soft, short bearing boolits in 9mm will sometimes fail to stabilize due to extremely shallow
rifling being fairly common. Try a harder alloy (this is a relatively rare requirement, and I
usually counsel to not sweat hardness) and see if this helps.

9mm is a bit of a booger, often having wide barrel dimensional variation and fairly common to
have very shallow rifling.

Bill

[fredj338]

SOme bullet styles/designs just won't shoot with some powders in some calibers. I found 9mm very finciky. My first attempts w/ W231 & two diff 124gr bullet designs were terrible. Not keyholing, but terrible accuracy. All I did was switch to Unqiue, magic, like shooting a completely diff gun. I suspect the bullets could be skidding a bit, & maybe larger would work, but try another pwoder before giving up on the mold.

[landers]

Well I had some time today to experiment unfortunately I learned a few more thing that didn't work, I feel like Edison and the light bulb.
1. Just to appease my curiosity I filled the hollow point cavity with alloy to see if maybe the HP was creating to much weight at the rear of the bullet and causing it to be unstable. Well it didn't, work but i figured if I didn't try it I would never know.
2. I then sized the bullet up .005 to my largest die, a true .3571, and to my surprisese the key holes got worse! these were completely sideways at 10 feet, not egg holes or the every other one, it was every round and completely sideways. I noticed the bullets were impacting about 4" lower on the target as well, higher pressures perhaps?

Next I will try reducing the load and maybe trying to find another powder to load with as Larry, easymoney, and fredj338 suggested, if I can find any around here. Another idea suggested by, I believe, Dusy and a fellow shooter whom I hold in high regards is that the short bullet is having to travel to far in the chamber before engaging the rifling, allowing gas to get by or allowing the bullet to enter the bore crooked. Just another couple of ideas.

Mtgun44 - I don't want to go to a harder alloy and lose the malleability for the HP. I have tried other alloys to get the BHN up but then the bullets fracture and you get unreliable penetration. Yes both of these guns have what I consider shallow rifling compared to my revolvers or my .45 acp 1911.

PS Paul - the guns I have tried are a Ruger SR9 and a EEA witness.

gefiltephish - both guns have extremely clean bores and both shoot my 147gr HP using the same alloy and sizing die with great success.

My final option - Agree with Dusty that my gun does not like this bullet and sell the mold to someone with more patience than I.

If I missed anybody I appologize, I will keep everyone updated.

[runfiverun]

landers all the info seems pretty scattered.
however the info given is all stuff that has worked to cure different problems.
there is one more thing I have seen work in the new guns which is contrary.
it is sizing smaller.
a lot of the new guns come without a throat this will strip the lead back and cause leading in the barrel.
it could also be letting your boolit just slide down the barrel without any [or not enough] spin imparted to it.

[CPL Lou]

I would examine my boolits for flaws first. I noticed that some of my hollow point boolits had a void where the bottom of them (bottom of hp, not base of boolit). Weighing will uncover the flaws. Next, I would try a slower powder like Unique, HS-6, or Blue Dot.
Also, look at one of your loads after it has cycled through the action by firing. Is one side of the boolit shaved or smashed ? If it is, you may have to adjust boolit hardness or spring strength.

[HeavyMetal]

The 147 fly straight. 115 don't.
We can rule out crown issues and other such problems.

What boolit design are you dealing with? I am also think casting flaws as well

[MtGun44]

IME, the Lee 356 120 TC with conventional lube is a design which is accurate and reliable in
many different 9mms when sized to .357 or .358 for some guns. Use NRA 50-50 lube to start,
air cooled wwt alloy, start with .358 and make a dummy round to see if it will chamber. If it will
make up 5 or 10 and try them.

Bill

[landers]

Finally, nice round holes in a perfect group!
Well I had a little time after work to look at this and finally found success. I worked the HP-38 load down a total of .6gr which is .3gr below the minimum data in my books, I worked it down slowly. The groups tightened up and had nice perfect round holes. I got so caught up in casting and bullet fit that i forgot the basics of reloading. This is the first load I have ever had to load below published data to get to shoot well. Now I just need to shoot some volume to check for leading and maybe a little expansion testing of the HPs. This mess also has shown me how valuable a chronograph would be, I believe I will call Chrony tomorrow.

Correct me if I am off base here. If the HP-38 has to be down loaded below available data to work would it be logical to use a slower powder like HS-6? Is this the correct direction?

Runfiverun - after reading your post I took a close look at my chamber and found something I had never noticed before. The throat is not square to the bore, I have rifling almost all the way to the chamber except at the 5 and 6 O'Clockclock position where the rifling starts farther down the bore. Just eyeballing the barrel from the chamber you can see that the throat is not concentric to the bore I don't know it this is common.

Thank you for all for the input and help. I have learned so much and everyone here kept me in a positive mindset which really helps solve problems.

Landers

[runfiverun]

no i'd think that is a flaw.
changing to a bit slower powder like unique can help gain some velocity back

[MtGun44]

What gun it this? If the throat is obviously very asymmetric, I would consider sending the barrel (alone)
back to the maker - unless they want to fit a new one rather than just replace, some are not considered
drop in parts. Some makers, like Ruger are amazing at working with customers, others - not so much.

Bill

[landers]

What gun it this? If the throat is obviously very asymmetric, I would consider sending the barrel (alone)
back to the maker - unless they want to fit a new one rather than just replace, some are not considered
drop in parts. Some makers, like Ruger are amazing at working with customers, others - not so much.

Bill

Bill the gun is a EAA witness, I almost hate to send the barrel back because it inherently has been a very accurate pistol. This is one reason I was having fits with this new cast HP bullet, the pistol has always been a good test bed. The Ruger SR9 throat seem to be fine through visual inspection but is actually less accurate than the EEA.

runfiverun - thanks for the input, I will start hitting the shops, all two of them, for a slower powder and try it.

Landers