Skidding?

[bruce381]

I have cast and relaoded for about 40 years and never really had a problem but the more I read here I'm now trying to treak things maybe looking to solve problems that are not there.

Anyway 44 mag S+W 29, 231 @ 6.0 gr 240gr WW mixed with some dead soft lead maybe 75/25 ratio in a Lyman 429421 boolit with LARS BAC Lube sized 430-4305. barrel may have a choked at the frame bore is .429 I get slight leading in the corner of the grove a inch or so after the forcing cone. I this skidding due to too soft? Also same load/gun I get a heavy buildup kinda a ring of lead only on the bottm edge of the forcing cone.

Never really noticed or had a concerns till I started reading here, Guess I better to not know and be happy.

In 375 mag or 41 mag no issues just this model 29.
Thanks
bruce

[GP100man]

The choking will definitly cause problems (Leading)as the pressure goes up !

It gives the pressure a slight gap to squeeze by until ya boolit bumps back up to seal the bore , some firelapp the bore to fix this .

As far as the forcing cone goes the axis of the bore may be low .

Most people think of the cylinder being "timed" left to right to prevent "spitting" but being lined up up& down is just as important !!!

Some opt for Taylor throating the forcing cone , it makes the transition frm cyl to bore a smoother "ride" for the boolit .

Taylor throating makes the throat longer ,thus allowing a little more pressure to escape (not thru the cyl gap) around the boolit & will drop FPS 100fps or so , but will decrease group sizes in most revolvers when shooting lead boolits .

But as you said, if accuracy does`nt drop off & ceanup is acceptable to ya do you really have a problem ????

As far as the skidding goes , & we can open a can of worms here if not carefull !!!
Fit & bullet hardness have to be balanced to acheive optimum performance from any firearm !

The hardest alloy can`t withstand gas cutting or bore riding!!

I`d say your fairly balanced with the alloy & load & if ya change either 1 ya leading will increase .

[Bret4207]

"Skidding" is 44mans term for stripping. The boolit enters the breech and the theory is that the forward motion and pressure are more than the alloy can take and instead of beginning to turn with the rifling the boolit strips or skids for a distance.

GP brings up a good point- is alignment an issue? I don't mean just cylinder.forcing cone alignment either, what about your boolits in you cases? I have yet to meet or speak to anyone that routinely checks revolver loads for run out, yet that could certainly play a part in this.

Have you ever tried a boolit a thou larger? Can you? Might be worth a try. Also, have you checked to make sure your boolits aren't getting swaged down in seating?

[243winxb]

Never really noticed or had a concerns till I started reading here, Guess I better to not know and be happy If you read here to much, you will need to rebuild your M29. [smilie=w: Your light load @ about 900fps is not skidding. Keep on shooting and enjoy.

[44man]

That load should be OK. Small amounts of lead that clean up easy is OK too. Accuracy is what counts in the end.
I have only one way to find skid and that is with recovered boolits.
Lead where it is at can be caused by other things and even a GC boolit with no skid can lead a bore.
Any mechanical problems need addressed first if there is a real need.
I have found by making boolits harder and harder for fast powders, accuracy increased as long as I have a good boolit fit. I think it is due to maintaining boolit shape.
However softer boolits do not cause me any leading even down to a 50-50 mix but oven hardening them aids accuracy and a GC really improves them because I do believe there is some skid past the base band or boolit damage.
Dead soft lead is another story and they can slump into a blob and even squirt lead from the gap. If you lose lead from the base through the gap, there is no way to get a good launch at the muzzle.
A lot depends on the initial thump of the powder and instant pressure rise to determine an alloy change but it is mainly to change accuracy. But saying too soft is good is not right because it will lead, no doubt.
Thinking it will expand to obturate and also expand again after a tight spot or even take the rifling in the first place might not be a good way to think about it.
Without all this blather, I should just say to make the boolit fit so no further expansion is needed, make it tough enough to take the rifling, keep the original as cast shape and you should have few problems.
Working for maximum accuracy is another story and where alloys need to be tried. Slower powders also help.
Some skid at the front of a boolit is OK as long as it does not increase the base rifling marks larger then the rifling.
Another thing to try is a different boolit. The 429421 is a decent boolit but it still has the Keith shoulder and a nose that will not steer it through the cone into the rifling. The nose is smaller then the bore. The boolit can not compensate for a few thousandths misalignment. It will just shear the little shoulder on one side.
Try a RNFP or LBT style.
If the Keith is too soft, it can slump and the nose might slump off center.
Long winded as usual! :bigsmyl2:

[bruce381]

I have a saeco mold #428 (44man recomended) trucanted mold but I can not for the life of me get if to fill out real sharp I get about only 80% keepers.

I get a funny void/bubble on the side randomly I think the ww soft lead I use needs some tin. Mold has a kinda oxidized patina. I will clean it good and try ladle pressure casting.

I have shot the 428 boolits and at 25 yards it is about same as the keith with really no leading to speak of. But the keiths spits a bit when I'm against the lane wall the 428 does not.

But I do get (with both boolits) the small bit of lead in the corner of the grove only about a 5-10 thousands wide I'd guess kinda where the boolit takes the torque or bits the the rifleing.

I will try straight ww or maybe some mono type mixed in to.

Even tho after a few boxes cleanup is only about 5-8 stokes of a brass
brush abd the bore is clean as a mirror.

But I have been real happy with casting as I said till I started reading here about how I do it all wrong LOL. I like to try different things out and still learrn a lot here.


Thanks
bruce

[bruce381]

bye the way the range I shoot will not let yopu dig around for boolits in the back stop so i cannot recover any.

[44man]

bye the way the range I shoot will not let yopu dig around for boolits in the back stop so i cannot recover any.
Makes it hard but boolits must be caught without mashing up so you might be lucky if you find one to read at a range anyway.
I don't think it is your alloy but go ahead and keep testing.
When you try the ladle, it will not be real pressure pour but after tipping the mold and ladle up, hold the ladle there for a few seconds longer so the cooling boolit will pull molten lead from the ladle instead of the sprue. That should fill the mold.
Tin might help but I quit using it with WW's, too expensive and I never found a difference worth the price. If your metal has been depleted of tin, that might need a little but never over 2%, over that does nothing.

[Bret4207]

That load should be OK. Small amounts of lead that clean up easy is OK too. Accuracy is what counts in the end.
I have only one way to find skid and that is with recovered boolits.
Lead where it is at can be caused by other things and even a GC boolit with no skid can lead a bore.
Any mechanical problems need addressed first if there is a real need.
I have found by making boolits harder and harder for fast powders, accuracy increased as long as I have a good boolit fit. I think it is due to maintaining boolit shape.
However softer boolits do not cause me any leading even down to a 50-50 mix but oven hardening them aids accuracy and a GC really improves them because I do believe there is some skid past the base band or boolit damage.
Dead soft lead is another story and they can slump into a blob and even squirt lead from the gap. If you lose lead from the base through the gap, there is no way to get a good launch at the muzzle.
A lot depends on the initial thump of the powder and instant pressure rise to determine an alloy change but it is mainly to change accuracy. But saying too soft is good is not right because it will lead, no doubt. That would depend entirely on what kind of charge you're using, what your goal is. Dead soft can work, it may just have a smaller window to work within though.
Thinking it will expand to obturate and also expand again after a tight spot or even take the rifling in the first place might not be a good way to think about it. Agree 10000000%!!! Depending on obturation to fit a boolit is going backwards IMO.
Without all this blather, I should just say to make the boolit fit so no further expansion is needed, make it tough enough to take the rifling, keep the original as cast shape and you should have few problems.
Working for maximum accuracy is another story and where alloys need to be tried. Slower powders also help.
Some skid at the front of a boolit is OK as long as it does not increase the base rifling marks larger then the rifling.
Another thing to try is a different boolit. The 429421 is a decent boolit but it still has the Keith shoulder and a nose that will not steer it through the cone into the rifling. The nose is smaller then the bore. The boolit can not compensate for a few thousandths misalignment. It will just shear the little shoulder on one side.
Try a RNFP or LBT style.
If the Keith is too soft, it can slump and the nose might slump off center.
Long winded as usual! :bigsmyl2:

I think we have to allow some leeway for peoples wants and expectations. A guy shooting a 45 or 38 at 850 fps isn't going to have the same pressure issues as a guy shooting a 454 at 1300.

[44man]

Bret, that is true but I am getting close to 57 years with revolvers and pure, pure with tin, then more tin, gave me the worst results and the worst leading.
Then I joined the West Cleveland rifle and pistol club. I was already doing gunsmith work so I got the job of cleaning the policeman's guns because the department shot there. .38's with soft wad cutters. Oh my, more lead outside then the boolits in the bore. Do you know how hard it is to clean lead from a blued gun without hurting the finish?
I was at that time shooting the Ruger flat top and the S&W 29. I used harder boolits and Hornady bullets. That started my learning curve and the testing with all alloys.
Yes, Elmer was the inspiration to shoot 400 yards and beyond but did you know he used some real hard lead? He talked a lot about lead and tin but he had different applications for it.
I have shot pure lead since I started to shoot---with black powder. That would be around 58 years.
Soft can shoot and I will agree with you but not dead soft. Antimony and tin starts to make boolits. Better alloys shoot better.
It always comes down to smokeless. No steady burn with a cushion behind the boolit, powder and fouling. More instant pressure, more distortion, more skid.
Light smokeless loads and low velocity does not mean initial pressure can not damage boolits. A few gr of Bullseye can make a blob of a boolit.
Yep, they WILL come out of the barrel! :veryconfu

[felix]

Be aware of any impulse response of any kind, and seriously consider how it can be minimized when using smokeless power. The energy delivered by smokeless powder is SUBSTANTIALLY greater than that from black powder during ignition as well as later down the barrel. ... felix

[Bret4207]

Bret, that is true but I am getting close to 57 years with revolvers and pure, pure with tin, then more tin, gave me the worst results and the worst leading.
Then I joined the West Cleveland rifle and pistol club. I was already doing gunsmith work so I got the job of cleaning the policeman's guns because the department shot there. .38's with soft wad cutters. Oh my, more lead outside then the boolits in the bore. Do you know how hard it is to clean lead from a blued gun without hurting the finish? Yup, dead easy, a little 4/0 steel wool and some oil. Been there, done that, got the tee shirt!
I was at that time shooting the Ruger flat top and the S&W 29. I used harder boolits and Hornady bullets. That started my learning curve and the testing with all alloys.
Yes, Elmer was the inspiration to shoot 400 yards and beyond but did you know he used some real hard lead? He talked a lot about lead and tin but he had different applications for it.
I have shot pure lead since I started to shoot---with black powder. That would be around 58 years.
Soft can shoot and I will agree with you but not dead soft. Antimony and tin starts to make boolits. Better alloys shoot better.
It always comes down to smokeless. No steady burn with a cushion behind the boolit, powder and fouling. More instant pressure, more distortion, more skid.
Light smokeless loads and low velocity does not mean initial pressure can not damage boolits. A few gr of Bullseye can make a blob of a boolit.
Yep, they WILL come out of the barrel! :veryconfu

I have no issue with your experience, just saying "different strokes for different folks".

[44man]

I have no issue with your experience, just saying "different strokes for different folks".
Yes, OOOO steel wool is what I used but I used it with Hoppe's. Kroil might be good.

[DukeInFlorida]

This place will fix skid marks:
http://ology.com/sites/default/files/imagecache/post-image/we-fix-skid-marks.jpg

Oh.....

lead...........

um..............

never mind...............

:mrgreen:

[44man]

I love it! :mrgreen::mrgreen::drinks:

[para45lda]

I have to say on one hand I am so much happier since I found this site. The info the life experience and yes even the agreeing to disagree.

On the other hand sometimes I think ignorance would have been bliss. [smilie=b:

Wes

[HammerMTB]

http://i172.photobucket.com/albums/w15/HammerMTB/Boolits/DSCN1748.jpg

Here's a pic of what I think is being referred to as skidding. The rifling don't take instantly so at the nose of the boolit the rifling witness is wider. You can see that before the gas check, the boolit started to spin at the same rate as the rifling so the witness marks are all equal.
This was a light load of fast powder in a .44 Mag. Vel was ~1000FPS.

[felix]

Perfect showing. ... felix

[44man]

Yes, nothing wrong at all. The gas check worked for what it was designed for and those boolits should shoot very well.
Thank you for the picture.
You can decrease the skid by making boolits harder but once a boolit works, it is OK. A perfect base is all that is needed.

[Bret4207]

Skidding, striping, same thing. There are a couple other terms for the same thing I can't recall at the moment.

You can also decrease the skid with a larger boolit, different powder, different seating depth...it's all about the pressure curve.

[KYCaster]

http://i172.photobucket.com/albums/w15/HammerMTB/Boolits/DSCN1748.jpg

Here's a pic of what I think is being referred to as skidding. The rifling don't take instantly so at the nose of the boolit the rifling witness is wider. You can see that before the gas check, the boolit started to spin at the same rate as the rifling so the witness marks are all equal.
This was a light load of fast powder in a .44 Mag. Vel was ~1000FPS.




Also a good illustration of SLUMP.

Any idea why the boolit on the right shows more skidding and more slump?


Jerry

[44man]

Also a good illustration of SLUMP.

Any idea why the boolit on the right shows more skidding and more slump?


Jerry
Use harder lead.
Slower powder.
If you are using magnum primers---stop. Soft lead has little case tension and some boolits might be going out of the brass before good ignition. That causes pressure changes and velocity changes.
The misconception is that light loads have low pressure but that is final pressure not where it is first applied to the boolit.
The boolit skid has been stopped at the base OK, now get rid of the slump.
That boolit should shoot decent but if you want extreme accuracy, maintain boolit shape. The easy way is harder lead, water drop.
The harder the lead, the more case tension you can use without sizing boolits while seating.

[EDK]

My tuned up early 629 S&W has been gathering dust in the safe for a long time since I got heavily into VAQUEROS for Cowboy Action Shooting...maybe 5 years. I also checked out the 624 I bought and have sadly neglected...got it at a price I couldn't resist 3 years ago. When I got them out and did some looking, I found some things you might consider.

I have sizer dies for the STAR in .430; 431; 432 and now .433. The .432 will slide through the throats in both S&W guns...433 won't. Low end loads had leading in the VAQUEROS with brinnell hardness around 15...dropped back to 10-to-12. The RANCH DOG TLC 432 265 boolit will remove residual lead if gas checked and dip lubed per the tutorial he did. I run six of them through every 200 or 300 rounds.

Your 6.0 of 231 load with 429421 is a bit light in the 20+ VAQUEROS and soon the S&W, that I cast and load for. I went to approximately 7.0 of HP38/231, HERCO, TITEGROUP, or RED DOT/PROMO, using either MIHEC or MMA10MM's clones of the Keith boolit (and a bunch of other designs too.)

Give your gun a good cleaning...use a CHOREBOY for the leading; try some of the suggestion ONE AT A TIME and see what happens.

:cbpour::redneck::Fire:

[HammerMTB]

Also a good illustration of SLUMP.


Jerry

Define SLUMP

[geargnasher]

Slump is nose deformation due to the **** trying to pass the nose on launch. The static inertia of the unsupported nose portion can be greater than the yield strength of the alloy if the pressure hits the base too fast, so the boolit nose "slumps" or "sets back", literally collapsing and flowing back against the rifling before it finally gets accelerating at the same speed as the base. Just like hitting a baseball with a bat vs. hitting a rotten orange.

You can tell the difference between a boolit mushroomed at landing vs. one slumped upon firing by looking at the length of the rifling marks. It's possible to get a "skid" appearance to land engraves from a mushroomed nose, but it's easy to tell what's going on by measuring the recovered boolit's diameter to see if it's significantly bigger than it was when it came out of the barrel.

Gear

[44man]

Define SLUMP
Slump!
It can be so bad all the grease grooves can be smashed away before the boolit even enters the bore. Another cause of severe leading, no lube at all in the bore.

[44man]

Some think a good lube will hold the GG's open---naw, it flew the coop, out the gap or back along the brass.
Lots of ideas and theory's but you really need to see these things for yourself.
Most revolver accuracy is simple mechanical solutions.

[303Guy]

HammerMTB's boolit on the right shows shank slumping. It's the base that's out of alignment with the boolit - or at least that's how it looks to me.:?:

[Bret4207]

Sorry, but I don't see any slump in that pic. Unless you put the boolit into a non marring, very soft catch material telling the difference between slump and impact expansion is pretty tough.

[geargnasher]

Nah, Bret, not tough at all. Like I said measure the amount of swelling at the nose and where the engraves end at the nose, measure boolit length and compare to an unfired one, and then you can hazard a reasonable guess as to how much was slump on firing and how much was slump on impact. If the engraves are significantly longer on the the recovered boolit than on a boolit tapped through the bore with a rod, you know the slumping occured in the bore, because nothing will make the engraves longer after leaving the barrel.

Gear

[Bret4207]

You lost me Gear.

[geargnasher]

Huh? How did I lose you? Are you baiting me into another one of my famous long-winded reiterations? Well, it's WORKING :kidding:

You said it's tough to tell between impact expansion and slump occuring in the barrel. I pointed out that you can tell the difference by measuring distortion of the boolit diameter/length, and length of the engraves.

If a boolit slumps in the bore, it will be a tad shorter, and the engraves will be longer than one that didn't slump, because the nose set back, squashed out, and increased the bearing length and thus the engraving length. If the nose slumped on impact, the boolit will be a lot shorter, and the engraves will be the same length or shorter than on a fired boolit that didn't slump on impact OR firing, plus the nose diameter will be larger than groove diameter on a boolit that slumped on impact, and the engraves will be wider at the front due to the overall diameter swell, not to be confused with wide marks from skidding.

Gear

[Bret4207]

I guess what I'm asking is how are you recovering boolits that aren't impact deformed. Only with FMJ do I ever find any of those. What are you shooting into?

[44man]

I use a 55 gal plastic drum full of rubber mulch. Works fine and only boolits that run into each other will show smashing.
Gear is correct with the rifling marks on the nose. Longer means more slump. Those marks are not increased by hitting something and mashing the nose.
The boolit sitting crooked looking in that picture is due to the camera.

[243winxb]

http://i338.photobucket.com/albums/n420/joe1944usa/Lee358-158-RF.jpg The one on the left was loaded over 17 grains of Lil' Gun. The one on the right was loaded over 13 grains of Lil'Gun. The one in the middle is not fired.If you exceed Lees Maximum pressure you will get Plastic deformation

--------------------------------------------------------------------------------
castboolits.gunloads.com/show...5425#post35425

Quote:
This whole relationship centers around the elastic limit for the alloy you are using and what the elastic limit is. the elastic limit is the point at which stresses can occur to an object and it will return to it's relative shape. Once you have reached the deformation stage it no longer returns to relative shape. this is a very simplified version of this topic as it pertains to engineering mechanics of materials.

This is meant to be a guide and to keep you within safe/acceptable limits for pressure and alloy for your purposes. Obturated bullets do not mean that the shape has went through plastic deformation, just that it has expanded and stayed within the elastic limits of the alloy.

The formula does not take into account other factors that aide in reducing friction and thus combined forces on the cast slug. As stated above, one member is getting very good accuracy with soft (by most peoples standards) alloys in high velocity loads (for cast anyway).

Another factor not talked aobut is the pressure curve of the powder/cartridge combination. Does it spike quickly (fast pistol powder in rifle size case) or is it a gradual increase (full case of slower powder). Protection of the bullet base can also be a factor, we routinely do this by gas-checking, using lube wads, or fillers.


http://en.wikipedia.org/wiki/Plasticity_(physics) plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces Obturate means to block or obstruct.

[geargnasher]

I use a 55 gal plastic drum full of rubber mulch. Works fine and only boolits that run into each other will show smashing.
Gear is correct with the rifling marks on the nose. Longer means more slump. Those marks are not increased by hitting something and mashing the nose.
The boolit sitting crooked looking in that picture is due to the camera.

I do the same thing, only I use a steel drum filled with about 20 bags of rubber mulch from Wallyworld per ideas from JimInPhx's invention and experiementations.

Gear

[HammerMTB]

Any idea why the boolit on the right shows more skidding and more slump?


Jerry

I asked the definition of slump so we would all speak the same language. Slump seems to me to be of the nose of the boolit, not the base. If it were the base, we could call it plastic compression.
The boolits in the pic do NOT show nose slump at all. Their nose dims are identical to boolits pushed thru the barrel with a dowel.
There is more to the story. The base of the boolit on the right is deformed. There is a reason why, as well.
Here's the deformation, from a different angle:
http://i172.photobucket.com/albums/w15/HammerMTB/Boolits/DSCN1749.jpg
Looking at the boolit base, you can see where the GC has deformed to the side facing the camera. The side was previously not shown, and the boolit tilted toward it. It could be mistaken for slump. One reason for asking for the definition of slump was to make the point that often a conclusion is drawn before all the evidence is examined. Note the void on the shank of the boolit on the left.
Now look at this pic:
http://i172.photobucket.com/albums/w15/HammerMTB/Boolits/DSCN1750.jpg
The boolit on the right again shows the base collapse. This was a void in the boolit that was compressed by the powder charge's thrust. The boolit on the left had an even larger void that allowed the GC to be pierced by the powder gasses, and blew out the side of the boolit, no doubt where the void was closest to the surface and could relieve pressure easiest. What surprised me is the lack of gas cutting at the site. The other thing that surprised me is that these were reasonably accurate loads. Those kind of voids and errata one would think would lead to some horrible accuracy. Not so much....

Don't let first looks fool ya! :brokenima

[geargnasher]

If it looks like a duck, quacks like a duck, and walks like a duck, it's a duck until further evidence proves it to be something else. That's what I go on. It looked to me that the base had compressed on the one on the right, just above the GC, and had done so unevenly but it's hard to tell from the angle. The one on the left had longer rifling marks on it's nose, telling me that the nose had slumped upon firing. I've recovered and measured a bunch that looked just like ieither of those two depending on the load, but never any with voids like that, that's impressive and even MORE informative than the first pic.

Gear

[Bret4207]

Okay, got it now, my bad. I saw what you guys meant, just didn't click.

[44man]

Impressive voids---WOW!

[white eagle]

:smile: Skidding?
wipe twice [smilie=f: