A hazard from gas checks?

[wallenba]

I had a conversation with a knowledgable gunsmith and caster last week whose opinion I respect....but question a bit. It was about the 'hazard' of seating a gas checked boolit below the neck. I am forced to do this with a few of my loads just so they chamber. Also, the seating depth given in many cast loads in the Lyman hand book and others, do exactly that. I seat them out when I can. His assertion is, that the check can become dislodged when engraving the rifling, come off, and become an obstruction for the next shot. My own intuition tells me that the check could not stand up to the forces behind it, and would be blown out under ANY circumstance.

I'm not going to alter my loads, as I've never, in many thousands of shots, ever worried about it. Yet, I am a knowledge seeking type individual, and would like to know more about this if anyone has an opinion.:?:

[Bill*]

My gut feeling says the same thing as your intuition. I don't see a check holding back that kind of pressure.

[largom]

By his "assertion" that the rifling could pull the check off what difference would it make where the boolit was in the case neck? I could see the possibility of an improperly, too loose, installed check falling off if seated below the neck but if it's in place when the powder ignites it's going out the bore with the boolit.

Larry

[wallenba]

By his "assertion" that the rifling could pull the check off what difference would it make where the boolit was in the case neck? I could see the possibility of an improperly, too loose, installed check falling off if seated below the neck but if it's in place when the powder ignites it's going out the bore with the boolit.

Larry

Perhaps he meant when the check met the bottom of the neck itself, and I took it to mean engraving the rifling. But I would think that the case neck would already have expanded under pressure before the boolit began moving forward.

[GOPHER SLAYER]

In a brief explantion to a qustion on the subject by a caster, the NRA said the reason you should not seat the gas check below the neck was because it allowed the hot powder gases to erode the bullet before it left the chamber. As for a primer being caught and sticking in the barrel, even discounting the powder, the primer alone would blow the primer out of the barrel. I know that because I have done it. I realized I forgot to put powder in a case after I had seated the bullet. When I pulled the bullet the gas check stuck in the case neck. I chambered the case and pulled the trigger. The case check made quite a projectle in my work shop. How did I know I didn't charge the round with powder you ask? The powder was still in the pan on my scale.

[btroj]

Yeah, and microgroove barrels won't shoot cast, wheel weights will wear out your barrel due to the dirt imbedded in them, and cast bullets must be hard to shoot well.

Any other old wives tales we want to discuss?

[uscra112]

"It's not that our opponents are ignorant, it's just they know so much that isn't true." (Ronald Reagan)

Never ceases to amaze me how often I see this adage proven.


Phil

[wallenba]

"It's not that our opponents are ignorant, it's just they know so much that isn't true." (Ronald Reagan)

Never ceases to amaze me how often I see this adage proven.


Phil

My first instinct was to argue against his warning, but he's a caster too. That does not mean he's infallible because he's a gunsmith. (His shop has done great work on three of my firearms in the last 16 months.) I think I'll just nod politely should the subject arise again. If he avoids loading that way, no harm to him, so it's not worth arguing the point. I might need his services again soon.
I never burn a good bridge.

[.22-10-45]

Hello, everyone. Perhaps he had a bad experiance, as I did when shooting my very first cast-bullet load.
It was early Spring of 76' I was getting ready to test my first cast loads in a Rem. 700 .222Rem. Bullet was the Lyman 225438..probably a WW alloy. I couldn't find any crimp-on gas checks in area, so bought the Lyman push-on type.
I was all set up on the 100yd. range..bore sighted & loaded first round. at the shot, I saw dirt fly at backstop & small hole near bottom edge of target paper..normal for the low velocity start load & eye-ball bore-sight. I am about to load another...when a little voice in the back of my mind (guardian angle?) suggested it might be wise to have a look thru bore?
Even after 36 years, I can still remember sitting there arguing with myself why I should do this...hadn't I seen dirt fly? And there was a hole in target paper! Besides, gun was all set up..if I pulled bolt..would probably be moved & next one would be out. Finally I gave in & had a look. Bore choked with powder smoke..as I blew it out, I took a quick peek...See just as I thought....But wait..what is that? kind of looks like a shadow? As I peer closer, there is a gas-check sitting in bore about 1" back from muzzle..edge-on to me..I nearly missed it!
Now I wonder, would the compressed air from ahead of next bullet fired blow it out? Or perhaps the bullet nose push it out? Or more likely, with my luck, it would be pushed aside & run over..ironing it into bore!
I have never had that happen again...But that was the last time I ever used a non-crimping gas-check.

[shotman]

I dont know about sticking in bore .BUT do know they will make history out of a crono when . they come off at 10 ft.
I just dont do it now

[tjones]

Ever think about these so-called PB checks made of .004 thick metal and rifling groove depths of .004 for the typical 30 cals.......duh. tj

[DukeInFlorida]

Swipe your finger quickly through a candle flame! Oh?? No burning, no pain???

I don't think the back end of a cast bullet, with some lead exposed inside the case, will see heat long enough to matter. The boolit will quickly be out of the case, sealed against the lands and grooves, and being pushed against by the pressure. No issues there. What really makes more of a difference with a cast boolit traveling down the barrel is the friction between the lead and the steel of the barrel, hence the need for a lubricant. And, also the hardness of the lead and the sizing of the boolit, so that the boolit gets the gases properly sealed behind it.

Your gunsmith's opinion is that the gas check will come off when it touches the lands and grooves? Every cast bullet gas check is the last thing to touch the lands and grooves. I don't get that logic, unless he's suggesting that the gas check gets pulled off hitting the beginning of the neck. Isn't the friction as the gas check comes in contact with the neck the same friction as the gas check sees when seated inside the neck area?

If the gas check is too loose to start with, I suppose there might be some potential for gas check to get pulled off as it contacts the neck area. I would shoot a few, and look inside the case after every shot, for signs of a loose gas check. Statistically, the more you shoot with no gas checks getting stuck inside the case will confirm that this is all a non-issue. My guess is that we all seat some gas checks that are somewhat loose, even if seated inside the neck area. I've never had one of the loose ones come off and get stuck in a barrel.

On the other hand, if you do find some loose gas checks, let us know.

I'm very surprised someone hasn't already studied this whole subject.

[GRid.1569]

I imagine the process to be: as pressure increases the brass of the case "moves away" from the bullet to create the gas tight chamber seal (the case is just a gasket of sorts during firing) - as the shoulder & neck have moved away; the leading edge of the Gas Check has nothing to catch upon before the bulet has started up the barrel....

....just as I see it....

[mold maker]

Unless the check has already fallen off, it will exit the barrel when fired. If it moves into the stream of pressure, it can't resist going with the flow.

[Ben]

I've shot a bazillion rounds with cast since 1967.
I'm certain that a high % of the rounds had g/c's seated below the neck.

Never experienced a problem.

Ben

[jhalcott]

I tried a bunch of Lyman "push on" checks years ago. Comparing them to "crimp on checks. Shooting thru a cardboard sheet at 15 yards, I got many 2 for 1 holes in the sheet. Meaning the checks came off quite often if not crimped on. I tried the same thing with checks below the neck on 30-30 ammo and shot into a Duct Seal target at 25 yards. Many of the uncrimped checks were missing. The bullet bases were often damaged a little where the crimped checks had good bases. I shot these loads at 100 yards for accuracy and the crimped checks always seemed to shoot better. This was with an OLD single shot 30-30 that I wasn't too worried about blowing up! Years later I tried some of the UNcrimped checks on 45-70 loads and got about the same results compared to crimped ones.

[Ben]

The original post said " and the g/c become an obstruction for the next shot."

The real question is.....Has anyone every experienced this and knows that this was the cause of the barrel obstruction ?

Ben

[felix]

If a block of snow within the barrel(s) can bulge the barrel(s), then probably a gas check or two will too. Yes, snow did cause an egg-in-the-snake look on two 20 gage barrels after climbing over a barbed wire fence with gun in hand (which is a NO-NO anyway). ... felix

It has to do with the rate of change of pressure. Not enough time for the rising pressure to clear the obstruction. ... felix

[Ben]

Felix :

Back to the question......Is there proof by anyone who can attribute a bulge in a barrel to a gas check that was seated below the neck line ( in a real life experience - not theories ) and knows that it also caused an obstruction in the barrel , then a damaged barrel with the next round that was fired.

In other words...who has proof that this has actually happened before as a direct result of a g/c obstructing a barrel ?

Felix, I'm not saying it can't happen, but I want to hear from the individual and hear their story on the subject .

I'm aware that snow and mud can bulge shotgun barrels. That is a fact. But....on the subject of a cast bullet with a gas check seated below the neck line of a case in a center fire rifle ....what actual proof is there that damage to a barrel has occurred before ?


Ben

[rbuck351]

If the GC was to fall off into the powder before being fired, there is a good possibility that it may not clear the barrel. If the GC is still on the back of the bullet as in still held to the back of the bullet by the neck tension, I don't think there is any way for it to not clear the barrel. Lots of pressure behind it with none in front. This is my guess as to why you should keep the GC in the neck. If you have a good crimp on check, I can't see it coming off in the bore whether seated in the neck or in the powder.

[geargnasher]

I'm in the "never had an issue with seating below the neck" camp, but that means nothing really, maybe I've just been lucky. I wonder how many errant checks have been shot out of barrels without any issues except perhaps an unexplained flyer or two.

I DO feel the need to remark on Duke's statement about the lead melting wive's tale. The hand-through-the-candle-flame analogy isn't accurate. It isn't heat that damages or cuts boolits, it's gas pressure. If you pass your hand quickly through a 30,000 PSI air jet, it will cleanly and instantly slice off your fingers. Gas-cutting can and will occur at any point that there's an obturation failure (gas leak past the boolit). There usually isn't a sufficient pressure differential to cause a rush of powder gas to damage any portion of a boolit seated below the neck. Sometimes boolits seated below the neck don't shoot well, sometimes they shoot fine, it just depends.

Gear

[tomme boy]

PSI is the cutting agent. We used a broom to check for steam leaks at one of the factories I worked at. It would slice them bristles right off. This was around 300 psi steam.

[softpoint]

I cannot see a gascheck being "pulled" off as the boolit passes through the neck. The boolit is not being "pulled out the case, it is being pushed. There is pressure on the exposed shank of the bullet inside of the case at the moment of ignition, but there is far more pushing the base of the boolit . Even a very long boolit seated flush with the case mouth, with most of the boolit below the neck will still be pushed down the barrel, even with a very light powder charge.

[0verkill]

The only hazard I could imagine would be slip on checks that jarred off in transport or in the mag. Might get enough push to get out of the case but not be centered and stick in the barrel. Then the billion to one odds i would reallign it's self to form a perfect gas seal on the next shot. I still don't see it happening.

[wallenba]

I have always been under the impression that if a check that comes off, it comes off inside the case after seating, because it was not on tight enough, and fell on top of the powder. Or, came off in flight.
This topic came up with him after I asked if he could increase the leade in my K31 so I could have more cast boolit choices. Currently I use the Lee C309-155-2r. The double radius ogive seats out farther than a 1r.

[jhalcott]

Considering the fact that SOME of the checks came off the bases before going ten yards and hit the cardboard sheet a few inches from the bullet,I am sure they DO come off! Either in or JUST out of the bore. In .30 and .45 caliber guns too. I do not know the reason they come off, be it air pressure as they exit, like a drag parachute, or a drop in "PUSH" at exit. I do know they are moving very fast. I heard from a friend of my grand dad that HE found a check IN THE EMPTY CASE after a hunting trip. I never saw this nor heard of it happening to any one else.. I DID hear about and saw the gun that had a 30-06 FMJ jacket stick in the bore. The noses of surplus ammo had been ground off and reloaded into the cases. The next shot bulged the barrel very badly.

[GRid.1569]

... and if the check did come off.. there's still a lot of powder behind it, turning to gas to eject it from the bore...

it's only copper... still relatively soft and any "resistance is futile"....

[mold maker]

If The boolit leaves the barrel caused by the expanding gas, the check has the same vel because the gas is still behind it. Just how in heck could it come to a screeching halt while still having all that pressure behind it? Even if it turned side ways and allowed some gas to pass, it would have very little drag in the bore and would still exit with the pressure.

[milprileb]

Is this a debate of if there is a crash noise when a tree falls in the woods when no one is there to hear it?

[felix]

No, Ben, I have not ever had a check come off that I know of. Once a projectile begins to move, the expanding gas migrates to the center of the moving object, thus pressing on any gas check. This alone would significantly lower the probability of a check doing any twist-and-shout. ... felix

[Ben]

Felix,

A g/c coming off a g/c bullet and damaging a barrel may be possible, I'm no Physics expert ?

If someone has experienced a C/F rifle being damaged from a g/c that fell off the shank of a bullet and damaged a barrel, I simply am requesting them to step forward and tell their story, as I'd like to hear it.

Ben

[waksupi]

I'm with you guys, I think it is a non-problem, until proved otherwise. That's a lot of pressure coming out of the chamber, to leave a gas check floating around in there. I don't think it can happen, and is another old wives tale that needs put out to pasture.

[wallenba]

I'm with you guys, I think it is a non-problem, until proved otherwise. That's a lot of pressure coming out of the chamber, to leave a gas check floating around in there. I don't think it can happen, and is another old wives tale that needs put out to pasture.

My conclusion early on.

My impression of why a check separates after leaving the muzzle is this. The rim of the check is dragging in the bore, as it exits it acts like a drag chute and is pulled off. Imparted spin makes it depart trajectory. After sizing the boolit, and seating the check, often the check diameter is larger due to springback, and that may be the root cause.

[jhalcott]

I remember trying the check BELOW the neck in that old 30-30. The loads seated deep did NOT shoot as accurately as the check in the neck! BUT< I did NOT tweak those loads to see if accuracy could be improved to the point of the longer loads!?? Groups were only marginally larger in the short loads. Not even enough to eliminate them for hunting use. I assumed the longer run to the lands and possible increase in pressure caused the accuracy loss. I experienced the same accuracy problem in a short throated .308. I solved that with a bore rider mold of the same weight!

[bobthenailer]

IMO perhaps this could happen with the Lyman non crimping gas check but not with the crimped on Horndays.

[MBTcustom]

A week ago, I would have sworn that it was impossible for the gas check to come to rest anywhere but downrange, but in another thread, there is another feller that says that he found a gas check in a spent casing. He just posted it yesterday in another thread.
Caused me to do some quick soul searching. Assuming that you are using aluminum home-made checks, and assuming that you were depending on the powder or COW, or filler of some sort to keep the gas check on the neck, I guess that could explain this strange phenominon.
Personally, I always try to seat the boolit as deep in the throat as I can, and that practice has never allowed the gas check to go below the neck. However, one of the things that has been drilled into my head a couple of decades ago, was that the check needs to stay in the neck of the brass.
I suppose I don't know for sure. Its another one of those things that I thought was correct. Castboolits.com has shot all my other dearly held suppositions strait to the third circle of hades, so I would not be surprised if this is another one of those areas.

[David2011]

This may not be an apples to apples comparison because it involves straight walled cases but I'll toss it out anyway. My rattlesnake loads are 5 grains of Win 231 in a .45 Colt case. I seat a gas check over the powder cup up, fill the case with #9 shot and top it off with another gas check cup down, secured with a heavy roll crimp. I've had the gas checks go through test targets and even turn sideways and slice through snakes leaving a pretty nasty wound. Not a problem; death of the rattler was the intent anyway. Point being, the gas checks always leave the barrel and they aren't attached to boolits. FWIW.

David

[btroj]

I could see the old slip for Lyman's being deep seated causing a potential issue. If seated below case neck and handled roughly a check could fall into the powder. Not sure if it would end up in the barrel or not but it could happen.

With crimp in checks it should never happen. Make sure they are on tight and go shoot.

[.22-10-45]

Hello, everyone..interesting posts! Now as to that long-ago gas check stuck in brl. load..I was using a Lyman load..I'll have to check those old notes..but it was probably a fast shotgun type powder..I wonder if a low muzzle pressure from that fast burning powder in a 24" brl. would allow an uncrimped check to remain in bore?
Now if you guys think a stuck check is strange...How about this....I was shooting an unusually light 260 gr. cast-lead bullet in an Axtel 34" barreled .40-70 2 1/2" straight. I was using a never before tried powder..IMR4227. These were to be light target loads...so I had used 1.0 gr. Kapok filler..stretched out like cigar & gently inserted into case mouth..this was not compressed, but left loose. .030" fiber wad on bullet base. First shot went OK..saw bullet impact 100yds., 2nd.shot felt normal also..but as is my habit..I lkie to blow thru & have a peek inside just to make sure it's clear. Bore choked with smoke..blowing woudn't clear.
I felt obstruction right in front of chamber. Thinking I had a bullet stuck, & not wanting to push it thru 34" of barrel..I gently inserted rod from muzzle & pushed out. What came out of chamber looked for all the world like a shotshell overpowder wad. That kapok had been compressed into a quite firm .40 dia. disk 1/4" thick..fiber wad was on end.
Now can someone tell me how a kapok wad ended up at the breech end of a 34" long barrel AFTER the bullet cleared muzzle? (this 2nd. shot bullet impact was near 1st. one).
No damage was done to rifle..but I did not shoot any more of these loads.

[Bullshop]

This may or may not have much to do with the question or situation but I feel should be tossed in anyway.
I was loading for a Marlin 30/30 using the long parallel sided 200gn LFN/GC from LBT.
It had to be seated so deep that the gas check and about three drive bands were exposed inside the case. I was shooting a duplex load with a very slow burning main charge. On inspecting boolits recovered from the dirt berm I could clearly see indentations on the exposed area the shape and size of the powder kernals. I guess the load was building pressure slowly enough that the forward part of the compressed powder charge was pressing against the sides of the boolit before it was pushed from the case.
The thing is the load shot so blasted good I adopted it as a favorite. Maybe I was just lucky?

[buck1]

With NO proof of anything, I have always seated the check in the neck Just to be sure. The odds are it will be fine . But the odds of winning the lottery are insane , but someone wins it every week too. I control every thing I can and cant justify taking a chance.
But to each his own. My $0.02 worth.

[bulet shotter]

Ok,so you are saying that any straight wall load you would not have to worry about a check coming off. I have pulled some bullets on my gascheck 44 and the check staied in the case,even though it was flat and hard to get out after I had pulled the bullet. Every time I think I have it all figured out someone comes up with some problem. I see that you are talking about a rifle load with a short neck and seating the bullet to deep,and the gascheck comming off. But I am sure with a straight wall 357,44,38 and 45 that you would never have a problem. David2011 ,I got to try that,what a way to make a birdshot 44. Jerry

[KCSO]

As long a a check is a crimp on there is no problem. When seating for a K31 almost all loads havve the check below the neck and i have never had one come off. As to it's lodging in the bore even if it's not on the base of the bullet it will still blow oout the muzzle. With the non crimped gas checks like we used in the old days it was not uncommon for the check to come off after leaving the bore, in fact I had several screens with check holes and dents. I have found cases that had the bullet seated deep where the check was found still in the case after firing, but in this case the check fell off before firing and there was no pressure behind it to force it out of the case. All that being said I still prefer to seat the check in the neck wherever possible, but if I can't I don't worry about blowing up the gun.

[tomme boy]

I was trying to find the OAL for a new boolit for my 308 last night. I had 4 checks come off when I was pulling the boolit because of it being too deep in the case. One came off when it was too long an was stuck in the throat. These were Blammers GC's. They were run threw my rcbs luber an sizer. I am not too happy about this as I never had a problem with Hornady doing this. I think the cup is not deep enough.

[MBTcustom]

I was trying to find the OAL for a new boolit for my 308 last night. I had 4 checks come off when I was pulling the boolit because of it being too deep in the case. One came off when it was too long an was stuck in the throat. These were Blammers GC's. They were run threw my rcbs luber an sizer. I am not too happy about this as I never had a problem with Hornady doing this. I think the cup is not deep enough.

I doubt that is the case. Hornady checks have a thick rim that actually bites into the boolit. It is created at the same time that they punch out the check. Easy to do if you have a 100 ton punch press. They probably knock out 1000 every 3-4 seconds. (I would Sooooo love to see that! Can you imagine the sound of 1000 gas checks falling onto a conveyor every 4 seconds? Music.)
Anyway, no homemade check is going to stay on that well, but if the cartridges are loaded correctly, its not a problem.

[tomme boy]

One thing I noticed was these checks are not as tall as the Hornady ones. Thats what I was wondering about if they just did not have enough to hold onto the base?

[357maximum]

Once upon a time not too long ago I bulged the rifled barrel on a Mossberg 835Slug barrel with a brand name factory loaded super duuper sabot slug. It knocked me clean out of the chair and spun me about but no serious harm was done. I was fine, the bystandes were fine, the gun itself was fine. The barrel was not fine...... Upon closer examination you could see a definate impression of one of those plastic gas seals that the factory uses below the stack of filler wads. I sectioned the barrel and sent it and the empty hulls/loaded rounds back to the company that made the slugs. They bought me a new barrel and about 6 months later that slug loading was discontinued.

I think that when it was being loaded the gas seal got pushed sideways into the powder charge (MANUFACTURING FLAW)and then everything else got pushed on top. When fired the gas seal likely came to rest midbarrel from lack of push but the filler wads propelled the slug out the bore. When I shot the next round things got interesting. One of the bystanders to this incident said something did sound slightly odd on my previous shot but that previous slug landed in the group with the rest of the other slugs. I did not notice the "odd" sound and the slug made a hole in the paper so i fired the next one....thats when I fell out of my chair.

Things can and will happen and all this was a straight hulled case....just happened to be plastic and at lowere pressure than the subject at hand.

[MBTcustom]

Once upon a time not too long ago I bulged the rifled barrel on a Mossberg 835Slug barrel with a brand name factory loaded super duuper sabot slug. It knocked me clean out of the chair and spun me about but no serious harm was done. I was fine, the bystandes were fine, the gun itself was fine. The barrel was not fine...... Upon closer examination you could see a definate impression of one of those plastic gas seals that the factory uses below the stack of filler wads. I sectioned the barrel and sent it and the empty hulls/loaded rounds back to the company that made the slugs. They bought me a new barrel and about 6 months later that slug loading was discontinued.

I think that when it was being loaded the gas seal got pushed sideways into the powder charge (MANUFACTURING FLAW)and then everything else got pushed on top. When fired the gas seal likely came to rest midbarrel from lack of push but the filler wads propelled the slug out the bore. When I shot the next round things got interesting. One of the bystanders to this incident said something did sound slightly odd on my previous shot but that previous slug landed in the group with the rest of the other slugs. I did not notice the "odd" sound and the slug made a hole in the paper so i fired the next one....thats when I fell out of my chair.

Things can and will happen and all this was a straight hulled case....just happened to be plastic and at lowere pressure than the subject at hand.

Thanks for posting that very relevant tid-bit!
I have been fed so much rumor in this hobby, that I have come to regard personal experience and experimentation as the last word, and its very hard to argue with the logic of your post.

[Oklahoma Rebel]

one thing is, I always anneal my gas checks, so there is no bounce back. they always fit tighter than the un- annealed checks . one thing I would like to know, is are all gas checks the same height? I know tome boy said that hornadies were slightly taller, but I am speaking for the 9.3X62, and I don't think hornady has caught on to that cartridges existence yet. but out of the other brands, is there any that are taller than the rest? I think that would help if your boolit is slightly below the neck-Travis

[Oklahoma Rebel]

so far I have only found that gator checks, and a "supplier" for buffalo reloading makes 9.3 checks, does anyone know who that other supplier is