gas cut barrel?

[compass will]

I was in the gunshop today for powder for the 22-250. I asked the guy does he shoot 22-250 and what powder does he use. I told him I only plan to shoot a couple hundred to break the barrel in before I start shooting cast.

he said "I would not mess with the cast if I was you, you will end up cutting a gas grove in your barrel? What is he talking about?

[Tom W.]

Never heard of such....Maybe he was thinking of throat erosion?

[docone31]

I was also thinking throat erosion. I am not sure, but the 22-250 was known for that. Suprisingly, the 22-06 was not.
I have to wonder if the throat erosion was caused by the round, or the reloaders. Today, we have a lot of different powders to use to match the bullet with the load.

[compass will]

I thought you would have less throat erosion pushing Gas Checked cast at 2300-2800fps then you would pushing condoms at 3800fps?

[Ricochet]

Will's right.

[docone31]

There is a BIG difference between jacketed and cast. The powder charges will also be different.
Up untill recently, I did not think a .22 would even be a realistic casting for centerfire. Of course, that was sitting around the wood stove listening to the Good Ole Boys at a young age. I wonder today, if they even knew what a reloading die was.
I bet a cast 22-250, or 220 Swift might not be a nice load. I am not going to make one, but I bet it is possible, and probably done.

[JIMinPHX]

The Swift & some other hot .22s in the 4,000fps arena were famous for throat erosion, but that was before we had the cooler burning powders that we have these days. Gas cutting usually refers to what happens in a .357 Maximum revolver when you get too horney with the powder charge. The gas that slips by the forcing cone cuts into the top strap. Again, I mostly heard about this happening in the early days of the .357 Max. I have not see examples of it in a long time.

[docone31]

Oh, boy. Back then, I had a Dan Wesson .357 Maximum. I shot IMHSA heavily. I also built an XP-100 in 338-06 Ackley and my buddy seeing that and not to be outdone spent the off season building an XP-100 in 460 Weatherby. Another story when we get the Darwin Awards sticky started. First shot did break his wrist.
At any rate, I could actually watch my top strap get plasma cut. I loved that pistol, it shot like a dream. I would go to Monson and they would give me a cup of coffee and time it, reface the forcing cone. One time they replaced the frame it got cut too thin.
I had all the toys for that pistol, grip, sights, and the best combination was as it came out of the box. Period. It was a shooter and did it real well. I had an underlug barrel sleeve made for it and they relieved it so it came in under 72ozs.
I cannot help it. I still remember my buddy shooting that hand held artillery piece. One shot and the pistol was in pieces! He was in the creedmore position and BLAM! broken wrist, front sight flattened to the barrel, beautiful kevlar grip in pieces, his blast shield with an hole in it, the snow missing from under the muzzle when he fired it.
If there were the Darwin Awards for that day, he would have won it. He saw me with my Ackley and I am a large person who used to spend hours in the gym every week. I remember, he was grinning and told me he loaded it HOT. He used to do that. He liked them fast.
I feel sorry for him. He really got hurt. He broke the radius and ulna and most of the carpals.
My Ackley really was not that bad to shoot. More like a .35 Rem on steroids. His field artillery piece, I couldn't believe he would do that. He had to one up everyone. I never saw him again after that. He gave up shooting as far as I know.
Those were the days.

[Wicky]

Will, did he have both hands in his pockets? Couldn't be that silly only playing with one!:rolleyes:
He has probably assumed you were using a revolver 'cause you were using cast boolits and didn't take any notice of the calibre. And everybody knows you only shoot cast in handguns - don'they?[smilie=l:

[Hang Fire]

I was in the gunshop today for powder for the 22-250. I asked the guy does he shoot 22-250 and what powder does he use. I told him I only plan to shoot a couple hundred to break the barrel in before I start shooting cast.

he said "I would not mess with the cast if I was you, you will end up cutting a gas grove in your barrel? What is he talking about?

Read as ignorance, or he wanted to sell you some high priced jacketed stuff.

[docone31]

I cannot tell you how much "information" I got from the Good Ole Boys at the gunshops I went to back in the '60's and early '70's and the things they taught me. Yet, I knew this older gentleman who was a black powder target shooter. What he told me was so simple I did not listen.
Today, I can remember what the Good Ole Boys told me vs the old guy. I use more of what the old guy told me than almost anything the Good Ole Boys told me was written in stone.
One shop owner was a gunsmith, actually a restocker. I purchased an Universal Carbine in .30 cal upon his reccomendation. Crapola.
Today, I think single shot, paper patch, sights. Not scopes, 30rd clips, etc. I even brought my carbine to him to fix. The front sight had cracked the mounting screw off leaving it threaded in the muzzle. He had the rifle for three months, ruined the barrel, and the screw was still in there.
They sold me my first Lee Handloader Kit in 30-30 Winchester. I loaded my first 20rds, and was afraid to fire the first one. Explosions, ringed barrel, flowered muzzle, all their words rang in my head. I finally let my friend convince me to let him fire the rifle. Less recoil, less flash, and was more accurate. I later found out those gurus did not reload, and really did not fire at any ranges. All their sage wisdom had little holes.
I have met many people since then. I have since learned, I have learned enough to want to learn more. But how their advice stuck.
I did later, snap another front sight screw off in another barrel. I made a tool to drill the center, and made a tool to reverse out the screw. They told me it was impossible.
Today, I wonder what is really impossible. Perhaps it should be said, practicle.
I bet he meant throat erosion.

[Uncle R.]

Lordy, I've heard so many of what Robert Ringer called "Schmexperts" that I pretty much ignore anything heard in a gun shop. Some of the dreck came from ignorant customers, but I've heard plenty from the dealer side of the counter too.
<
If you're not careful you'll be exposed to the same thing on the range as well. The good part is, all this flying bullspit has at least taught me to be careful about taking advice from unknown sources. It's also helped me to learn a little about people. The louder the mouth, the more the speaker seeks the agreement and praise of everyone around him, the better the chance that he's ignorant. It's far more likely that the guy who says it quietly - and ONCE - knows what he's talking about.
<
I'm only gonna say that ONCE.
:wink:
Uncle R.

[compass will]

Ok. being a newbe to the terms, trying to make the transition from being just "a good shot" to learning how to be a "better shot", I am allowed to ask this one.

What really is Throat Erosion, and what causes it?

I think the throat is the area between the chamber and where the rifling starts?.

If this is true, I guess that the bullet is leaving the chamber which is a little larger then the rifling and the throat has to stabilize it just a little bit?

Erosion is caused by a piece of metal (bullet) slamming into the throat at high speed.

If I am correct, I would assume that if one was to slow down the speed, or shoot a softer metal (cast) and you will have less throat erosion?

[Ricochet]

Yeah, out at the range I've encountered experts who immediately told me I'd have terrible bore leading and no accuracy shooting cast boolits in a rifle. One of them then proudly showed me his group he'd shot with his megabuck scoped AR-15, and got quiet when he saw the smaller group I'd just shot with cast boolits in my old Turkish Mauser with the original sights.

[GSM]

Will:

Throat erosion in high performance rounds is directly attributed to very hot, high pressure gases exiting the case.

[GabbyM]

Throat erosion is mostly caused by gas cutting. The higher the pressure the more throat erosion. So with cast bullets using low pressure loads your erosion is greatly reduced. For instance I can wear out a 243 Win barrel in under 1,600 rounds. Just a whole lot of powder going down a little bore at well over 50K psi. Hard jacketed bullets at 3,400 fps or above.
For that fellow to say you'd gas cut your barrel with cast bullets is totally reverse thinking.

Rifle barrels last a long long time at 40K psi and bellow. Regardless if you're using cast or jacketed. I believe they last even longer with cast.

That gun shop fellow may have run into someone who used max pressure loads under a cast bullet and eroded the barrel. Well duh. Twas the pressure along with volume of gas not the bullets.

You can push a 54gr boolit at 2156fps with 15.6gr of IMR-4227 and 13,800C.U.P. In a 22-250. That's from the Lyman book. That load will not burn out a barrel.

[Tiger]

I do not think it is pressure. One stated the higher the pressure the more the erosion. Take caliber that wears barrels fast such as 264 winchester magnum and 220 swift. Today there are many cartridges run higher pressure and way higher pressure and not wear like two mentioned.

Read this from the Finnish: Gunsmith Creighton Audette provided an interesting article from the March 1956 issue of the AMERICAN RIFLEMAN. This article, written by P. H. Naatanen, a Finnish army officer, described some testing they performed with a 2.087" long, rimmed Russian case firing 200 grain .312" diameter bullets. A total of 13,500 shots were fired through this barrel with measurements of both the throat length, angle, and groove diameter taken every 2000 shots. Represented on a graph, the throat angle seemed to advance at a somewhat uniform shape, and it moved forward at a rate of about .040" per 2000 rounds. The actual groove diameter for most of the barrel's length increased only .0002" in diameter. This was attributed to friction between the bullet and barrel. The writer and his associates felt that throat erosion was caused primarily by hot gases, not friction, and interestingly, that it may have been accelerated by an original throat diameter that was .0028" over bullet diameter. In theory, this allowed excessive amounts of hot gas to escape around the bullet and `burn' the throat even more. The crux of the experiment was that gas erosion and not friction caused the most wear on the throat and barrel. Also, the throat and leade angle seemed to wear at a fairly uniform rate, increasing both in diameter and length but closely maintaining the original angle.

I believed for long time it was combination of bullet friction hot gases and abrasive of powder particles.

Ralf

[AZ-Stew]

Will,

Though most of this thread has revolved around throat erosion, there is something else that probably should be mentioned.

The phrase "cutting a gas groove in your barrel" caught my attention. He may have been warning you about chamber neck ringing, a subject that has been discussed at some length here, with much disagreement remaining about whether it occurs. I've experienced it and it had nothing to do with "gas cutting". The discussion usually involves using or not using over-powder fillers, the type of material used and how it's applied over the powder charge. My recommendation is to use a slower powder that will fill the case without using a filler and still give the velocity you want for your cast boolits. Doing so will allow you to avoid the fillers and, in my opinion, eliminate the possibility of ringing the chamber neck.

That having been pontificated, I'll suggest H-380 powder for your break-in loads, working up from about 37.0 to a max of 40.0 grains (verify with published data before using these loads) with a 52 grain HP J-bullet and a STANDARD or Bench Rest primer. DO NOT use this data with Magnum primers.

One more thing about throat erosion... Shoot high-intensity cartridges, such as the 22-250 S-L-O-W-L-Y. No faster than 1 round per minute to allow the barrel to cool a bit between shots. If the barrel is too hot to touch, you're shooting WAY too fast. Remember, you're funneling an awful lot of very hot gasses and fast-moving powder particles from the cartridge body into a much smaller bore diameter. As others have said, heat is an enemy of rifle barrels. I own a .257 Roberts that chamber casts tell me was abused by a previous owner. The action parts show normal wear, but the first inch or so in front of the chamber looks like dried, cracked mud. The evidence tells me that the damage was caused by rapid firing, not by a great number of rounds having been fired. Amazingly, though, it still shoots decently. Not fabulously, but decently.

You won't need to worry about bore erosion as much with your cast loads. Keep the pressure down and I doubt that you'll ever cause any measurable wear in the bore. Clean gently. You're more likely to damage the bore with a cleaning rod than with cast boolits.

Regards,

Stew

[Ricochet]

The phrase "cutting a gas groove in your barrel" caught my attention. He may have been warning you about chamber neck ringing, a subject that has been discussed at some length here, with much disagreement remaining about whether it occurs. I think he was just repeating some ignorant bit of advice he'd heard without a clue what it really meant.

[docone31]

Upon teaching my wife to shoot targets, I told her, If you cannot kiss the barrel, put the rifle down and take a break.
From what I have heard about throat erosion, it is indeed produced by heat and the gasses. Breaking in the rifle is critical to me. Fire it slowly. Give the metal a chance to ease itself into permanent state.
I built a couple of .243s with stainless barrels. They are rifled to use 100gn. We will break them in slowly.