Probably this. May not happen with a lower pressure load. If the cases were as long as the chamber, or at least almost, probably wouldn't have the issue.Originally Posted by nvbirdman
Rick
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Probably this. May not happen with a lower pressure load. If the cases were as long as the chamber, or at least almost, probably wouldn't have the issue.
Rick
Like I said
Normally Palma chambers are not tight necked. If the chamber does not accept a standard service round it is not a rule complaint Palma chamber.
In the older days when the host nation provided the ammo all sorts of games were played to give the host nation an advantage. Undersize bullets being one. The Matches in South Africa in 1974 are a good example. A friend of mine was on that team. SA ran a special lot of ammo with undersize bullets. They had barrels made to match. All the other Nations Teams were at a significant disadvantage due to this within the rule "cheating". Later that was fixed with mandating the use of Sierra 155's but lots of Palma shooter still used undersize bores. Later other 155 grain bullets were allowed but the rule for chambers and bores got more restrictive with the Bisley Rule 150 specs.
https://forum.accurateshooter.com/th...isley.3781199/ Post #2 lays it out well and the OP was the US Palma team captain during that time period.
For chamber reamers I have the 308 Palma 95, the 308 Bisley, the 308 Bisley Rule 150 and a one other version I don't recall at this time. The one thing they all have in common is they must chamber a standard service round.
More on the Palma course of fire and rules. https://www.6mmbr.com/palmabasics.html
Last edited by M-Tecs; 03-08-2021 at 05:07 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
Too sharp of a lead into the throat, as Tomme boy said. It can be fixed by adding a bevel at the beginning of the throat.
If that is the case the reamer would have needed to be the non-throated type and the chamber was never fully throated. Handguns are a different matter. Some on them do have very abrupt leads or steps between the cylinder and throat.
These are match chambers. The SAAMI standard is 1 3/4 degree lead.
Last edited by M-Tecs; 03-08-2021 at 06:49 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
I had PT&G make my reamer for me. Its a one off. Basically a tight neck turkey palma match....This is a target rifle that i have made.... its been a few years, i dont remember the specs on it. I moved away from my old shooting buddies and dont get to play with it much anymore.
Deposited alloy in the space between the mouth and bore. Could be sharp edge OR just accumulated alloy 'dust' that gets packed in. I get it in my flash hider also. Basically same stuff that 'leads' the barrel (gas cutting) but never gets there. You neck size but what OD is the barrel neck? I don't use that mould but if the shank is short the GC can 'nip' the 'tail' (bore sizing) of the drive band and deposit it. Basically using a plug to push a marsh mellow through a larger - then smaller hole. AR10 is notorious that way, as are many auto loading pistols. Fortunately pistol HS on mouth - not much gap (actually most HS on the extractor).
Whatever!
Got a pic or a drawing of the reamer they used to chamber your barrel?
I have lost that information... i've moved to another state, and lots of things got "misplaced"...
Ahh, just curious about the neck to freebore transition area. I've run into what tomme boy described on several .35"-.45"straight walled cartridges if you push them hard enough for bullet obturation. Every time what cured it was lightly buffing the case mouth to freebore step to remove the sharp edge. I generally start with j-words and once they're running well add in cast. Pic is from working up a new wildcat using 200gr xtp's and Barnes 195 soilid copper. The rings were from the Barnes 195gr solid copper shown right above them and started forming in the mid to upper 40(s)K psi IIRC. Breaking the sharp corner on the casemouth to freebore step stopped the rings from forming even when using lead.
Listening to Johnny Cash's "RING OF FIRE" too many times will tend to do that!
HA....ha!
Have you tried pulling some bullets and seeing if the lead ring is present at that point?
The solid soft lead bullet is undoubtably the best and most satisfactory expanding bullet that has ever been designed. It invariably mushrooms perfectly, and never breaks up. With the metal base that is essential for velocities of 2000 f.s. and upwards to protect the naked base, these metal-based soft lead bullets are splendid.
John Taylor - "African Rifles and Cartridges"
Forget everything you know about loading jacketed bullets. This is a whole new ball game!
Ring of fire----when you reach for the Vaseline and get Ben-gay! (from : Ronnie Prophet at the Forum [Hermon the horny toad]).
R.D.M.
No I haven't, I may get some time to do that tonight.... good thought.
Buy an "M" die.
You sent a PM which was the exact right thing to do, and we can solve your problem by honing throats and then sizing your boolits .0005" under throat diameter. For example .4015" for throats and .401" for boolit diameter, it's merely a fitment issue that goes away when you achieve proper fitment.
However let's not steer the thread away from elginrunner's OP I have answered your PM Thanks! Doug
Got a .22 .30 .32 .357 .38 .40 .41 .44 .45 .480 or .500 S&W cylinder that needs throats honed? 9mm, 10mm/40S&W, 45 ACP pistol barrel that won't "plunk" your handloads? 480 Ruger or 475 Linebaugh cylinder that needs the "step" reamed to 6° 30min chamfer? Click here to send me a PM You can also find me on Facebook Click Here.
According to the drawings Mtec posted, the chamber has a sharp drop, 45 degrees before the throat. This is what's ringing the chamber. Normally these would not be too sharp IF the ID of the case that is just fired is the same as or very close to the ID of the beginning of the throat when the round is fired. Pulling a fired and cooled case would not be quite so accurate since it will have sprung back somewhat but it would be useful.
*IF* the diameters are the same, and there is no mechanical step down in diameter ahead of the case mouth, then obturation upon firing is the only source of energy with enough force to let the boolit grow in that free space ahead of the throat so that the throat is shaving it. It has to be bigger in order to be shaved smaller and leave rings behind.
If you offer a bevel more linear than the 45 degree chamfer that is already there, this will only serve to lengthen the amount of unsupported free space and allow the boolit even more room to obturate, and if you think ringing is bad now, you ain't seen nothing yet!
This explains the problem of where the rings are coming from, but does not address how to prevent them. You hit the nail on the head when you said you only used J-words previously, and the gilding metal is sufficiently thick enough to resist obturation or it too would be shaving rings.
The easiest thing to do is to A. go back to J-words, and if you still want to attempt to use cast, then B. alloy or coating or both have to be hard enough that no obturation occurs and it will quit shaving the boolits if they are not presented to the throat at a larger diameter from obturation.
The hardest thing to do would be to have the barrel set back enough that you can re-ream the chamber and use a reamer that has a sharper step at the case mouth which would transition into the throat without that unsupported free space in front of the case mouth. In so many words, get rid of the 45 degree angle, and put enough freebore in the throat that the boolit is supported as the round is chambered, set the ogive of the boolit back .025" or so from the leade ins and give it another try with cast.
Got a .22 .30 .32 .357 .38 .40 .41 .44 .45 .480 or .500 S&W cylinder that needs throats honed? 9mm, 10mm/40S&W, 45 ACP pistol barrel that won't "plunk" your handloads? 480 Ruger or 475 Linebaugh cylinder that needs the "step" reamed to 6° 30min chamfer? Click here to send me a PM You can also find me on Facebook Click Here.
The 45 degree angle at the end of the neck start of the throat is the most common. The SAAMI angle for a 308 is 35 degrees and 43 minutes. Same for the 06. The 8mm Mauser is 75 degrees. The 45/70 is 12 degrees and 45 minutes. The 458 Win Mag is 45 degrees. They all have a long history of working with cast bullets.
https://saami.org/technical-informat...mber-drawings/
Some nice visuals here http://castboolits.gunloads.com/show...esign-software
Last edited by M-Tecs; 03-10-2021 at 01:47 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
Case neck shorter than it should be?
Got a .22 .30 .32 .357 .38 .40 .41 .44 .45 .480 or .500 S&W cylinder that needs throats honed? 9mm, 10mm/40S&W, 45 ACP pistol barrel that won't "plunk" your handloads? 480 Ruger or 475 Linebaugh cylinder that needs the "step" reamed to 6° 30min chamfer? Click here to send me a PM You can also find me on Facebook Click Here.
I don't have a clue on this one. It's shaving material at some point but where? The OP ruled out it happening at bullet seating and or crimping. The pretty much leaves shaving at the gas check seating or as the bullet leaves the neck. If it's a gas check issue that's easy to solve. If it's a shaving issue at the neck throat/junction an alloy that more resistant to obturation might help. Same for a powder with a softer pressure curve. After that I have no recommendations or solutions. I also have limited experience with higher pressure higher velocity cast loads. Same for PC.
Until we figure out why the OP is having issues when most others don't with a similar set up we will be hard pressed to recommend a solution. If it was mine (if I ruled out shaving at check seating) I would lean towards looking at obturation. Alloy issue?, seating depth issue?, short brass?, tight bore?, pressure curve issue, an combination of a bunch of things or something else?
If it was mine I would first try seating the bullets deeper if they are close to the lands. It MIGHT be a simple as the base of the bullet riveting as pressures rises due to the bullet touching the lands. I don't think so but until it's ruled out it's possible. If it doesn't improve I would try a tougher alloy.
When I don't have a clue sometimes the only option it process of elimination starting with the simplest items first and hope for some change to at least indicate what direction to go.
Last edited by M-Tecs; 03-13-2021 at 05:32 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
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