Here's a mystery for you...


PDA






Snowdog
April 15, 2003, 04:19 AM
Today, I took the liberty of firing a few rounds into playdough from my .45acp Llama.

After the brief Playdough carnage, I noticed something I couldn't explain. Recovering the spent slugs from Playdough, I noticed that all 185gr Georgia Arms JHPs (G45AG) I was testing failed to expand. This is the only factory JHP that I know of that won't expand in Playdough.

However, the most interesting aspect was the spent slug itself. I noticed that on one side of the slug, there is a lot of powder residue, yet on the opposite side, there is hardly any. There were identical markings on all the slugs recovered. What do we know can causes this? Could there be something wrong with the barrel?

One side of .45acp is noticeably carbonized (left) and the opposite side is not. Is there some kind of gas blowby happening here, or some kind of conspiracy?
http://www.imagestation.com/picture/sraid60/pd52ac5fae674c7479d8622f76931dfdf/fc55c632.jpg

If you enjoyed reading about "Here's a mystery for you..." here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
Flashpoint
April 15, 2003, 04:30 AM
Hmmm. That is interesting. I don't have an answer for you, but I do have a question. Where do you get 60lbs of playdough?

Snowdog
April 15, 2003, 04:33 AM
Where do you get 60lbs of Playdough? Easy... go to the toy section of any Walmart and clean the shelves. Be prepared to spend about $80. :(

But, in retrospect, I don't think I could have done any better.

WonderNine
April 15, 2003, 06:16 AM
strange....very strange....

:D

New_comer
April 15, 2003, 07:44 AM
I'm just "imaginating" these so, here goes:

Try shooting at cardboard. If they keyhole, you might have a busted barrel. Also explains why the slugs dont expand: they hit the clay sideways...

Check also for rifling marks if they're present all around the slug, maybe to allow you to determine a balanced fit of the barrel around the moving slug...

Just a few of the possibilities. Hope these help.

hksw
April 15, 2003, 01:44 PM
Sounds to me like the concentricity of the lands to the grooves is off. That is, the grooves are more shallow on one side than the other. Could cause the round to tumble as New_comer mentioned.

DJJ
April 15, 2003, 03:29 PM
Could be your chamber isn't perfectly circular (like slightly egg-shaped). The case mouth may be expanding a little more into the oblong part and letting some gas blow past the bullet just as it's leaving the case.

What happens with other brands?

ajacobs
April 15, 2003, 04:35 PM
whewww, I though before i got to the picture that you were talking about their gold dots.

Mal H
April 15, 2003, 04:59 PM
That is interesting. You can see the land pattern on the darkened side of the bullet.

A few things I would check:
Use a caliper or micrometer on an unfired bullet from the same box and be sure it is both completely round and is the proper diameter.

Slug your barrel with a soft lead bullet and mike it all around. That will tell you if the barrel is out of round and what the actual bore dimension is. Actually, you may not need to slug the barrel but could use the recovered bullet since it was apparently not deformed by the Playdough. That would be valid only if the test of the unfired bullet showed it to be perfectly round.

Al Thompson
April 15, 2003, 05:53 PM
How's the pistol's crown? Have you tested for accuracy?

Snowdog
April 16, 2003, 12:02 AM
Thanks for the responses. I've been giving thought to slugging the barrel as well.


Have you tested for accuracy?

Yep, I was quite pleased with the accuracy of this little pistol. Though in a different catagory than my Kimber, it is more than adequate for just about any use I can think of (other than competition).
From this same pistol, I've tested Gold Dots, older model Black Talons, Hydra-Shok and Golden Sabers... all expanded in playdough. I'm thinking the lack of expansion is due to mild velocity and a poorly constructed JHP (there are no serrations to aid in expansion).

Freightman
April 16, 2003, 12:29 AM
I saw a strange thing the other day, went to the range and while I was setting my target at 25 yds I looked down and there laid a 9mm JHP with searations on the ground. After further investagation I found it to be a spent bullet by the land marks on it. What was strange is that it had hit the angle iorn frame flat and did not flatten out or expand it only flatned the tip.
The only thing I can figure out is that it was way underloaded as it miked out at .355.

Al Thompson
April 16, 2003, 08:00 AM
Well, if accuracy is good, there goes the crown theory. :)

Jim K
April 16, 2003, 09:48 PM
It looks to me like the barrel is slightly bulged out on one side. This could be due to damage of some kind, but it really does not surprise me in a Llama.

Jim

Brian Williams
April 16, 2003, 10:10 PM
Playdough receipe

2 cups flour
2 cups water
1 cup salt
1 table spoon of oil
2 teaspoons of cream of tartar
put in pan and stir and cook at low heat until mixed and doughy

this is cheaper than store bought
ohh
add food coloring for desired color

SDC
April 16, 2003, 10:16 PM
Is the chamber maybe not concentric to the bore? Other than that, I can't really imagine how gas blow-by can happen on one side of the bullet and not the other :confused:

blades67
April 17, 2003, 12:39 AM
Sounds like the problem is the bullets themselves. :scrutiny:

Dr.Rob
April 17, 2003, 05:49 AM
I'd suspect the case mouths on the factory ammo weren't crimped or that the brass wasn't circular, after all your other ammo doesn't show this.

If you enjoyed reading about "Here's a mystery for you..." here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!