Does it matter if GC comes off after Boolit leaves the muzzle?

[BAGTIC]

The area of "lowered pressure" only occurs after the bullet leaves the barrel therefore it would not have any relevance to a GC being caught in the bore. For several feet after muzzle exit the jet of escaping gas continues to exert sufficient pressure on the base of the bullet that it continues to increase velocity. That means the net pressure on the bullet base is still positive.

As for the issue of whether the GC has enough spring back to release its grip on the lead bullet base remember that the lead itself has been expanded (obturation?) inside the gas check the same way lead cores are expanded inside bullet jackets during jacketed bullet manufacture. Are we to believe that when a J-bullet leaves the bore the jacket expands enough to loose its grip on the core.

Personally I would tend to believe that a stray bullet found in the bore was there because it was detached from the bullet during the transition from the case neck through throat and at time of engagement with rifling.

[BAGTIC]

I doubt that frictionally induced heat ever gets high enough to melt the lead core. There simply is not sufficient time. Cores likely get much more heat from hysteresis caused by core deformation as it is shortened and expanded upon firing.

[robertbank]

I doubt that frictionally induced heat ever gets high enough to melt the lead core. There simply is not sufficient time. Cores likely get much more heat from hysteresis caused by core deformation as it is shortened and expanded upon firing.

Gas cutting on the surface of the bullet does take place and is the major source of leading. Like you, I doubt any melting takes place outside of the gas cutting. GC;s on my 9MM Hi-Tek coated bullets stopped the leading in it's tracks. I still suspect it is ny alloy., softened by baking that is the cause of my leading found at the muzzle end of the barrel. The base is just not strong enough to prevent gases getting buy and cutting through the coating and cutting the lead. The GC provides the seal. My 38spl HI-Tek bullets work just fine and the coating has stopped the leading found in the first 1/16th of an inch found when shooting lead bullets. I have a slight barrel constriction on my Ruger GP-100. Hi-Tek solved the leading for that gun when using 38spl loads. Things break down when I switch to .357 mag loads.

Take Care

Bob

[W.R.Buchanan]

I shot 50 rounds of .44 magnum reloads thru my Marlin 1894 CB 24" with Lyman 429244's GC's. I used 22.0 gr of H110.

My main reason for using this boolit over the 429421 is leading at 1600fps + .

The bore on this gun was so clean afterwards I didn't even clean it. It was literally mirror clean.

It's good to go next month unless I shoot it more this month.

None of the targets I shot could tell me if the checks were still on but I am inclined to think they were. I have no evidence to back that assertion up. It just feels right.

Randy

[robertbank]

Randy if they are coming off they will be on the ground in the first few yards. I have not had commercual GC's come off my rifle boolits but the plain base aluminum ones have come off my 39spl and 9MM bullets. Not all do judging from those I see on the ground but some do. I have seen no evidence the loss of thr GC has affected accuracy out to 25 yards. Rifle bullets using PB GC's might come off. I have not got there yet.

Bob

[Ballistics in Scotland]

I doubt that frictionally induced heat ever gets high enough to melt the lead core. There simply is not sufficient time. Cores likely get much more heat from hysteresis caused by core deformation as it is shortened and expanded upon firing.

I doubt if friction induced heat is very great in pistol bullets - to which this thread wasn't limited. But deformation heat is mostly produced in the bullet's first inch of travel. Any tendency to melt as a result will never be as great. Overstressed rifle bullets frequently fail to show lead trails on the target at five or ten yards, but do at twenty. That is because frictional heat takes time to penetrate through the jacket to the lead core.

This was a problem in the first experimental .303 bullet. One successful answer was to incorporate a layer of paper between cupro-nickel and lead. It wasn't used in production, since it was a complication and might impair concentricity. But a thicker jacket did the same work.

A bullet gets most of that deformation in the first inch or so of movement. But a bullet very often fails to produce lead trails on the target at five or ten yards, and does so at twenty. This is consistent with the heat taking time to penetrate through the jacket. It happened with the first experimental .303 rounds, and one successful solution was an intervening layer of paper between jacket and core.

Besides, how hot is a piece of lead when you hit it with a hammer and immediately tip it into your hand? There is some heat there, and it will turn into surface temperature eventually, but it is distributed throughout the bullet, and is conducted through a greater distance in poorly-conducting lead, than friction heat does through copper.

I was very sceptical about gas-checks detaching in the bore. If they do it, they do it in the open air. But suppose they don't have to detach? Occasional anecdotes may arise from the practice we sometimes hear of, of inserting a gas-check loose and back to front, behind the bullet. It sounds seductive, with the flange expanded by gas pressure to seal the bore, like a Minié ball. But it isn't attached, and is all to easy to push beyond the neck, so that it can turn over in the powder space. Even an airspace in the neck, between bullet and check, might do that.

I doubt if a gas-check is heavy enough to cause a classic ring-bulge, or even a burst. That happens when an obstruction is heavy enough to slow the bullet, and the gases catch up, as a pressure-wave. But it could easily tip over to one side of the bullet and cause a different kind of damage. There used to be a kind of continental European shotgun anvil which was occasionally spat out into the powder space, and those, followed by another shot, could form a distinctive dimple in the bore.

[Case Stuffer]

So in summary some say yes ,some say no and so it goes. What I find very interesting is the references to crimp on versus slip on gas checks. to the best of my knowledge no one makes / sells any crimp on gas checks anymore if I understand the defination correctly. I tried making reference to the difference between have a burr on the inside edge versus the outside of the cup but that point as dismissed by some and not commented on by others.

I believe that a gas check going off in flight from a small caliber high velocity rifle Boolits can have very negative results.

[jhalcott]

I have recovered bullets shot into wet pack that still had the checks attached. Also many bullets recovered from the berms had checks still on them. I believe Hornady makes their crimp on and Lyman slip on gas checks. Gator checks are as good or better than Hornadys

[SniderBoomer]

I found the only 'home-made' check that will surely never come off, are Plain-Base checks. I personally make mine using Pat Marlin's tools. They never come off even without using glue, I am very impressed with these.

The PB checks do need to be fixed onto boolits when the boolits are still soft, either immediately after casting, or, hardcast boolits immediately after oven-heating and quenching, but that's no big deal. Most of my new molds these days are ordered with a Plain-Base option, just to let me make use of these tenacious-gripping Plain-Base home-made checks.

Where I live, a 'pro' crimp-on check can add 6 cents a pop in the 44 and 45. PB checks make a lot of sense.

[Case Stuffer]

I believe Hornady makes their crimp on and Lyman slip on gas checks.

Perhaps however I have purchased 1,000 ea. Hornady .22 cal. copper gas checks two different times months apart and they are what most now call slip on. They do have a very slight burr on the inside edge however it is not thicker in this area that I can determin by very careful inspection / measuring.

[robertbank]

I found the only 'home-made' check that will surely never come off, are Plain-Base checks. I personally make mine using Pat Marlin's tools. They never come off even without using glue, I am very impressed with these.

The PB checks do need to be fixed onto boolits when the boolits are still soft, either immediately after casting, or, hardcast boolits immediately after oven-heating and quenching, but that's no big deal. Most of my new molds these days are ordered with a Plain-Base option, just to let me make use of these tenacious-gripping Plain-Base home-made checks.

Where I live, a 'pro' crimp-on check can add 6 cents a pop in the 44 and 45. PB checks make a lot of sense.

I hate to say this but my 9MM and 38spl bullets shed my PB GC`s about 50% or more of the time. I find them all over our pistol pits after a session of shooting. They work great though and I have found no evidence their leaving the bullet after exiting the barrel has any influence on accuracy at all. I install the GC`s using my RCBS Lubricator. Works great as well. I highly recommend Pat Marlins GC maker as his GC`s work in preventing gas cutting.

Take Care

Bob

[Larry Gibson]

GCs do indeed come off in flight and in many cases the accuracy is adversely affected. Crimped on GCs can also come off in flight (many times as soon as they leave the muzzle) if pushed to hard. I have posted numerous times on the loss of accuracy from such and the destruction of Skyscreens from the GCs on the HV with cast bullet threads and have included photo's of the damage and poor targets.

I have used thousands of the old Lyman slip on GCs and my own home made ones of aluminum and brass. In most instances the velocities of the bullets were in the 1600 - 1900 fps out of milsurp rifles. Accuracy was/is very acceptable (usually 2 moa for 10 sots) and since most are used plinking and informal shooting the loss of a GC and any loss of accuracy usually goes unnoticed. However, if you are serious about accuracy for competition then I suggest the use of crimp on GCs.

Larry Gibson

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[robertbank]

Larry GC`s coming off in flight may have a material affect when shooting rifles but at 35 yards and in shooting IDPA or IPSC the affect in negligible when shooting a handgun. I have to hit an eight inch circle in IDPÂ for a Down Zero. If it does have a material affect my shooting skills would never notice it.

Take Care

Bob

[Case Stuffer]

Snip from post #27

I believe that a gas check going off in flight from a small caliber high velocity rifle Boolits can have very negative results.

[popper]

This subject came up a few years ago, a guide with a 45/70 handy rifle (?) & lee loader didn't crimp the checks and found one in the barrel, according to him.

[outdoorfan]

I just completed load work-up on one of my rifles. I use pb gc's on bullets fired at 2000 fps. I've noticed a number of gc's several feet forward of the muzzle, and like Robert says, I don't think they are all coming off. Anyway, I've had good accuracy to 265 yards (the farthest I've shot to).

[fatnhappy]

not to be contrary: homemade gas checks aside, are slip on gas checks even available anymore?

Back to the OP, I can't help but believe the reason slip on gas checks are panned is the recognition by the CB community that introducing an uncontrolled variable is incongruent with basic quality control. I used a couple boxes of the old brass lyman checks in the 90s and lost one skyscreen to them. that's the last time they graced my bench.

[robertbank]

not to be contrary: homemade gas checks aside, are slip on gas checks even available anymore?

Back to the OP, I can't help but believe the reason slip on gas checks are panned is the recognition by the CB community that introducing an uncontrolled variable is incongruent with basic quality control. I used a couple boxes of the old brass lyman checks in the 90s and lost one skyscreen to them. that's the last time they graced my bench.

I guess that vary much depends on which of the many CB communities you are talking about. As a primary Action Shooting caster my alloy is WW alloy and a mixture of WW alloy, solder scrap, range scrap and any other source I find available. GC's would be the least of the variables I worry about. Distances are relatively short and if GC's prevent leading due to a soft alloy I might be using perfect. My rifle shooting under 100 yards works about the same way.

I have not found much difference in accuracy for what I do and likely would not notice the difference if there was any as, at 70, my eyes and reflexes are not what they once were. Scopes and sand bags help.

Do I use GC's, home made aluminum and commercial copper, yes. For the rifle with the molds I use...yes.

I do use them over my F! Chrony. No issues.

I suspect most of the above would drive a long distance bench rest shooter off his oats. Works for me and I suspect others too.

Take Care

Bob

[Duckiller]

Mold Maker Super glue is a great way to make GCs stick on. I had some that were slightly oversized for the boolit I was using. Sizing wouldn't keep them on. A small tube of Super Glue on my shelf solved any problem with checks coming off. You only need the smallest drop possible.

[Larry Gibson]

Larry GC`s coming off in flight may have a material affect when shooting rifles but at 35 yards and in shooting IDPA or IPSC the affect in negligible when shooting a handgun. I have to hit an eight inch circle in IDPÂ for a Down Zero. If it does have a material affect my shooting skills would never notice it.

Take Care

Bob

Bob

I was answering the OPs question in his 1st post opening this thread. He was talking about his AR in .223 and higher velocity rifle cast bullets. I understand the thread drifted to include other cast bullets at lower velocities but that was not the intent of my answer.

You are correct that at IDPA ranges with a handgun the effect is negligible but I was referring to rifles shooting cast bullets at longer ranges. Even then with tight fitting slip on GCs rifle cast bullets fired at lower psi's and RPMs most often don't lose their GCs and accuracy most often equals that of crimp on GCs. I shoot a lot of both kinds as I still have several caliber Lyman slip ons left and make my own .22, .30, .32 and .35 caliber GCs of aluminum and brass. The slip ons most often work well so I use them for a lot of shooting However, for match and HV use (Over 2200 fps) I use crimp on brass GCs. The loss of slip or crimp on (as I demonstrated in the above post) GCs does have a definite adverse affect on accuracy when it occurs at higher velocities.

I use my own slip on brass GCs in many 357 Magnum and 35 Remington bullets (358156 & 35-200-FN) in revolvers, Contenders and rifles with excellent results even at longer ranges because those bullets are pushed in slower twist barrels not over 2150 fps......they work fine there.

Good post notating the differences, appreciate that.

Larry Gibson