Keyholing

[Turnup]

Come on guys...

Measuring to "the tip" or "the point" will completely screw up anyone's reloading.

COL is measured to the ogive.

SAAMI and every reloading manual I have seen disagree.

Look at this diagram

http://saami.org/PubResources/CC_Dra...%20British.pdf

[Turnup]

I'm sorry but you just can't peddle that kind of nonsense - how did you come up with that idea, can you back that up with any real evidence or proof?

I have no evidence or proof other than personal experience. It happened to my Marlin .357. About one shot in three or four with target loads at 25 yards indoors. Flyers which also keyholed (not as badly as the OP has described). Brush the bore after every shot and it was shooting fine. 'Twas badly pitted about 2/3 towards the muzzle. New barrel job Also similar effects in a mate's 10/22 (which if you had read my post #7 you would already know) due to a ring bulge near the muzzle. That's two examples.

Now please explain your credentials and why you believe my post to be nonsense.

[Turnup]

What?
No-one told my .222 then
it has a stretch of pitted barrel about 2" long where half the rifling is gone!

shoots sub inch all day long
shoots cloverleaf holes from a bench and stabilises 60gr in a 1:14" twist....


OP, your problem is bore and groove diameter vs. bullet diameter check both

Sheesh! Just 'cos yours shoots fine, does NOT mean that ALL pitted barrels will shoot fine - effects vary.

[strebblo]

I have no evidence or proof other than personal experience. It happened to my Marlin .357. About one shot in three or four with target loads at 25 yards indoors. Flyers which also keyholed (not as badly as the OP has described). Brush the bore after every shot and it was shooting fine. 'Twas badly pitted about 2/3 towards the muzzle. New barrel job

Also similar effects in a mate's 10/22 (which if you had read my post #7 you would already know) due to a ring bulge near the muzzle. That's two examples.

Now please explain your credentials and why you believe my post to be nonsense.

You're asking someone on an internet forum for their credentials? Well done. I'm obviously the president of the NRA in space, and I also invented shooting. What's more is that ferrets are far more accurate target shooters than humans, but are not allowed to compete at club level anymore, so only a few of us who were lucky enough to be their apprentices have this knowledge.

Happy with that?


My point was that you were portraying your theory as some kind of fact, when you can't see what goes on in the bore and have built a 'fact' around a conclusion, based on a symptom that might not be related, from the evidence of just one rifle - at 25 yards? Come on, there's something else more serious going on if you can get your bullets sideways through the target in the space of 25 yards. 25 yards.

Your mates 10/22 with a bulge in the barrel is totally the opposite symptom to your pitted barrel. Two examples of not the same thing does not make any kind of statistical pattern.

Have a read of this: http://www.longrangehunting.com/arti...le-crown-1.php
that takes a commonly held belief that an absolutely immaculate crown is a must, and just smashes it. Those blokes went to quite some effort to still be unable to answer the question, and even then they could have been a lot more methodical and the experiment was far from exhaustive. But it proves the point to me that a lot of bollocks is talked by a lot of people who should be spending more time out there shooting and less time talking about it.

There are so many things in shooting that are unproven, but a few people come up with some things that sound plausible (sometimes not even that good) but without any proof or any thorough checking, and it gets lapped up.

I'm no expert, but I try to be methodical and question everything I do because this is a precision game. I know what I know until someone challenges that knowledge and if it can be proven or backed up then I need to learn from that.

My credentials? I'm a sceptic - give me a sound reason why you think your theory could be correct and why it can't be anything else.

...Because it's your theory to prove, not mine.

[zanes]

Come on guys...

Measuring to "the tip" or "the point" will completely screw up anyone's reloading.

COL is measured to the ogive.

Tac has said it already, but I'll just say: Seriously, what the ?

[Turnup]

You're asking someone on an internet forum for their credentials? Well done. I'm obviously the president of the NRA in space, and I also invented shooting. What's more is that ferrets are far more accurate target shooters than humans, but are not allowed to compete at club level anymore, so only a few of us who were lucky enough to be their apprentices have this knowledge.

Happy with that?

If you say so.


My point was that you were portraying your theory as some kind of fact, when you can't see what goes on in the bore and have built a 'fact' around a conclusion, based on a symptom that might not be related, from the evidence of just one rifle - at 25 yards? Come on, there's something else more serious going on if you can get your bullets sideways through the target in the space of 25 yards. 25 yards.

In one of my posts (#7 in this thread), when the OP revealed that this was happening at 20 yards, I did state that this was a pretty gross.

Your mates 10/22 with a bulge in the barrel is totally the opposite symptom to your pitted barrel. Two examples of not the same thing does not make any kind of statistical pattern.

The symptoms were similar, the ranges similar. No statistical pattern was claimed, but the evidence of just one example proves that it can happen at least once for each cause.

Have a read of this: http://www.longrangehunting.com/arti...le-crown-1.php
that takes a commonly held belief that an absolutely immaculate crown is a must, and just smashes it. Those blokes went to quite some effort to still be unable to answer the question, and even then they could have been a lot more methodical and the experiment was far from exhaustive. But it proves the point to me that a lot of bollocks is talked by a lot of people who should be spending more time out there shooting and less time talking about it.

I have not claimed that am immaculate crown is imperative. I do claim that a damaged crown can cause inaccuracy. Do you honestly believe that, while some barrels will shoot well with pitting or crown damage (outside of my experience but I am happy to accept the claims of others as possibilities), therefore pitting and crown damage cannot cause the reported symptoms?

There are so many things in shooting that are unproven, but a few people come up with some things that sound plausible (sometimes not even that good) but without any proof or any thorough checking, and it gets lapped up.

I'm no expert, but I try to be methodical and question everything I do because this is a precision game. I know what I know until someone challenges that knowledge and if it can be proven or backed up then I need to learn from that.

My credentials? I'm a sceptic - give me a sound reason why you think your theory could be correct and why it can't be anything else.

Show me where I stated that there can be no other cause?

...Because it's your theory to prove, not mine.

Not attempting to prove anything, just offering suggestions to the OP

You are the one who started asking for evidence.

You seem to be reading things into my posts which are not there.

The OP was asking for pointers to the cause of his friend's problem. I was not stating that the observed behaviour has an obvious cause, but listing some possibilities to look into, based upon some personal observations. I have witnessed a ring bulge cause similar behaviour at 25 yards. I have personally experienced severe pitting cause similar behaviour at 25 yards. Different cartridges to the OP's but still these are facts, when applied to the specific barrels which produced these effects. Therefore I believe that my theory could apply to the OP's problem. Review my posts and you will see that at no time have I stated that the symptoms can have only one cause, and no other, nor have I dismissed any other suggestions made (particularly the one regarding bullet fit).

[tacfoley]

SAAMI and every reloading manual I have seen disagree.

Look at this diagram

http://saami.org/PubResources/CC_Dra...%20British.pdf

Hah, you beat me to it there. I, too, have all the SAAMI documents regarding dimensions and pressures, but this being a rather 'loose' forum, I was not sure that I'd get laffed off for quoting documents used in the USA that are not generally known about here.

tac
Life Member NRA
Life Member DCRA

[amc577]

Just a guide.....you still need to work out the correct overall length for your bullet and your gun. The stated COL for the K31 is a bit of a laugh for my K31 ,rebarreled in 1957 and then put into store. Lands come down to the caseneck and run at about .295.....even GP11 needs a good tap to chamber.COL is meaningless for this rifle.

amc577

[tacfoley]

Just a guide.....you still need to work out the correct overall length for your bullet and your gun. The stated COL for the K31 is a bit of a laugh for my K31 ,rebarreled in 1957 and then put into store. Lands come down to the caseneck and run at about .295.....even GP11 needs a good tap to chamber.COL is meaningless for this rifle.

amc577

Do tell us more. I write on two Swiss forums and we are always interested in seeing and relating incidents like this. OT, I agree that you appear to have a problem - the K31 was designed from the get-go to shoot GP11 with no problems, and therefore has a very tight chamber by comparison with its predecessors, some of which had chambers like a wizard's sleeve. Using bullets of a different type without that long ogive of the GP11 bullet has always been a trial to reloaders, and it really needs costy Match Kings or Berger VLD bullets to get near the results achieved by the issue milsurp GP11, probably the finest mass-produced military ammunition ever made.

tac
www.Swissrifles.com
www.gunboards.com

[Turnup]

Hah, you beat me to it there. I, too, have all the SAAMI documents regarding dimensions and pressures, but this being a rather 'loose' forum, I was not sure that I'd get laffed off for quoting documents used in the USA that are not generally known about here.

tac
Life Member NRA
Life Member DCRA

Perhaps wrongly, but I regard SAMMI as a definitive source for safe cartridge and chamber dimensions, even those not originating in the USA. I believe that they take a lot of trouble to get it right (both foolhardy and brave not to) in the particularly litigious society over there.

[pjinoz]

I am posting this on behalf of a fellow club member. I am not knowledgeable about this subject so if I make a c*ck of myself please bear with me.

He has recently bought a Lee .303 and is currently tuning his self loads. He is meticulous in weighing his loads (Unique) and does everything the same for each bullet. However, he is getting the odd bullet going in to the target sideways! Last night he shot a card with 8 tens a 9 all lovely round cut holes but 1 end up in the 6/7 ring and was the perfect cut out of the bullet shape sideways on. This has now happened on a few occasions but it is just the odd one and not 2 or 3.

Any help, advice or pointers would be gratefully received by him as it is driving him nuts.

All the best

Mark

Hi Mark,
Assuming that the bullet diameter of your friends rifle closely matches its bore then it is very likely that the bullets that have keyholed have failed to "spin up" and have "skated" across the lands. Pitting if it is severe usually results in poor accuracy and not keyholing. I have loaded and fired tens of thousands of mostly FULL POWER lead alloy bullets (gas checked or plain base) in such calibres as .30 carbine, .318 WR, .360 Nitro, .375 H&H, .44 mag, .460 Ackley, .458 Win, .577 Nitro and .55 Boys Anti Tank and have come to the conclusion that providing the alloy is hard enough and you "accelerate" the projectile "slowly" you can achieve very high velocities with excellent accuracy. In your case the use of Unique whilst resulting in low MV may in fact accelerate the bullet too fast so that the softer lead alloy does not properly engage the rifling and fails "to spin up". Of course if the bullet is under diameter and has a large jump to the rifling then this makes life hard. To give you an example from my experience. I designed and had made a 250g .318 Westly Richards mould with gas check that mirrored the shape of the 250g solid projectile. Since I wanted to achieve 2400 f/s (factory ballistics) I cast bullets from linotype. However, initially I loaded quite a few rounds with 11 or 12 grains of Dupont 700x shotgun/pistol powder for a quieter load and to my dismay found that many of these long projectiles were "going sideways" at much the same range as your friend. MV was just over the sound barrier. Recovered sideways bullets exhibited little or no rifling whereas nose on ones had rifling. I came to the following conclusion that whilst this was a low velocity round with mild breech pressure it was "rammed" into the rifling too fast for engagement. What did I do? I loaded the same bullet with the same COL except I used 54g of DuPont 4350 for a MV of 2400 f/s, no leading, better than 2 inch groups at 100 yards and NEVER ANY KEYHOLING! "Slow" start into the rifling and a "long" acceleration to high velocity. BTW the use of a gas check does not prevent the bullet base from melting (you can quickly pass your hand through a oxy acetylene flame at 3300 degrees and not get burnt and that's slow compared with the time a bullet base is subjected to. Most likely the gas check acts as a driving band like the copper band on an artillery shell. Perhaps your friend can ensure that his bullets are of bore diameter, reduce the distance to the lands (if possible), check that his bullets are sufficiently hard and perhaps try a slower powder.

Cheers

[tacfoley]

^

Best post here so far. Just a couple of points though -

1. The OP's pal is shooting indoors, on what is ostensibly a pistol calibre range.

2. The range limitations here in UK with regard to maximum velocity [usually 1500 fps indoors] and bullet composition would bang any hope he has of firing ANY kind of high velocity, gas-checked, lead/linotype alloy on such a range.

Here in UK, it's lead only indoors or go somewhere else.

tac

PS - Linotype may now be found in museums here in Yoorup, so where do you get yours?

[pjinoz]

^

Best post here so far. Just a couple of points though -

1. The OP's pal is shooting indoors, on what is ostensibly a pistol calibre range.

2. The range limitations here in UK with regard to maximum velocity [usually 1500 fps indoors] and bullet composition would bang any hope he has of firing ANY kind of high velocity, gas-checked, lead/linotype alloy on such a range.

Here in UK, it's lead only indoors or go somewhere else.

tac

PS - Linotype may now be found in museums here in Yoorup, so where do you get yours?

Hi Tacfoley
My post was not necessarily aimed at high velocity but perhaps more importantly the possibility that Mark's friend problem could be solved by using a "slower burning powder" to more gently ease the projectile into the lands. However, this does not mean that one has to go the whole hog and use lots of very slow burning powder to achieve full blown ballistics; instead limiting the charge and type to the velocity you wish to obtain. If 1500 f/s is the limit then experimenting with slower powders than unique would be worth trying even though the charge weight will likely go up but max pressure and rate of burn go down. Now whilst the following example relates to a full throttle load try to understand why I did it. When I had my .577 Nitro double which originally used a a 750 g jacketed projectile propelled by 100 g of Cordite for 2050 f/s I had a plain based mould made to cast the same weight. Tried all sorts of powders starting from those of approx. Cordite burning speed of around 100 grs but could not get the accuracy I needed. I ended up using 140g of surplus 4831 (ex 20mm cannon powder) to achieve 2050 f/s, no leading, good accuracy and LOW pressure, in other words a gentle but more prolonged burn/acceleration.
Must admit I bought more than a 100 kg of linotype years ago and whilst those printing days are gone you still should be able to make up these sorts of alloys from a lead based metal supplier in the form of various other alloys such as high Antimony/Lead which you could blend up by the appropriate amount of Tin from solder. Of course at 1500f/s you do not need pure linotype and mixtures of linotype and pure lead can be used with success. As I also mentioned I'm inclined to believe that the gas check acts more as a "stronger" driving band than anything else.
Cheers and happy shooting

[amc577]

Just one other possibility.....someone has messed up the crown or part ofthe rifling near the crown with heavy handed rodding....seen this inermittent problem with a cz452.....examinationwith a borescope showed damage to the lands an inch or so fromthe crown.....gunsmith used a reaming tool to smooth out the damage.

amc577

[tacfoley]

Hi Tacfoley
My post was not necessarily aimed at high velocity but perhaps more importantly the possibility that Mark's friend problem could be solved by using a "slower burning powder" to more gently ease the projectile into the lands. However, this does not mean that one has to go the whole hog and use lots of very slow burning powder to achieve full blown ballistics; instead limiting the charge and type to the velocity you wish to obtain. If 1500 f/s is the limit then experimenting with slower powders than unique would be worth trying even though the charge weight will likely go up but max pressure and rate of burn go down. Now whilst the following example relates to a full throttle load try to understand why I did it. When I had my .577 Nitro double which originally used a a 750 g jacketed projectile propelled by 100 g of Cordite for 2050 f/s I had a plain based mould made to cast the same weight. Tried all sorts of powders starting from those of approx. Cordite burning speed of around 100 grs but could not get the accuracy I needed. I ended up using 140g of surplus 4831 (ex 20mm cannon powder) to achieve 2050 f/s, no leading, good accuracy and LOW pressure, in other words a gentle but more prolonged burn/acceleration.
Must admit I bought more than a 100 kg of linotype years ago and whilst those printing days are gone you still should be able to make up these sorts of alloys from a lead based metal supplier in the form of various other alloys such as high Antimony/Lead which you could blend up by the appropriate amount of Tin from solder. Of course at 1500f/s you do not need pure linotype and mixtures of linotype and pure lead can be used with success. As I also mentioned I'm inclined to believe that the gas check acts more as a "stronger" driving band than anything else.
Cheers and happy shooting

Thanks for the explainment. However, the rules here in yUK are as explicit as they are annoying. Only LEAD projectiles may be fired in an indoor range, not an alloy, not a bit of lead with a teensy little bit of something else in it, just lead. When the home Office Inspector of ranges, ors the person deputised by him to act on his behal, states that projectiles used in XYZ range are limited to lead, that is exactly what is mean. Lead. Bust. BTW, a gas check on a bullet makes it unusable on and indoor range.

Also, at the price of propellant powder here in UK, most folks try very hard to limit that amount they buy and try to find one powder that will do all the things they want to do I found that 4064 does for most every calibre that I shoot except for .45-70 Govt, .44 BP or .58cal Enfield or Snider.

tac [tac is enough, the foley is my surname]