Craigster, The throat in the 25.25 inch 1 in 10 twist Shilen barrel was eroded about .250 inches after 1500 rounds, and velocity was down about 90 - 100 fps.

Normally I would seat the Sierra bullet about .010 - .020 from the lands, but as the throat eroded, I chased the lands and increased the loaded length by seating the bullet further out in the neck.

I discovered that once the loaded length exceeded 2.900 inches in my medium length Rem 700 action, it would no longer feed reliably through the magazine. So with the loaded length at 2.9 inches I had .150 inches of jump to the lands but accuracy was still reasonable with the 69 grain Sierra's grouping around .6 - .75 moa as long as I kept on top of the barrel fouling.

About 6 months ago, I had the barrel set back and rechambered to 22/250 AI, and the barrel lost about .75 inches in the process and is now about 24.5 inches. Velocity with the 69 grain Sierra HPBT is down to 3,400 from 3900, but accuracy is terrific, with groups of .25 to .4 with numerous near maximum/maximum loads.

Conclusion to be drawn from this is that the barrel is obviously still in excellent condition despite 1500 rounds from the Clark.

Next time I build up a rifle for the .224 Clark, it will have a long M700 action, to allow the bullet to be seated further out as the throat erodes, and a 28 inch barrel with a 1 in 8 twist to stabilise bullets of 80+ grains.

A barrel of 28 inches will enable it to be set back and rechambered and still have sufficient barrel length for the .224 Clark.

The barrel life of 1500 rounds is the same as what I achieved in a .17/222 Mag, 22/250, 22/250AI, 220 Swift, 22O Swift AI, 22/284, 25/06 AI, and 7mm Rem Magnum.
Hope the above helps, Brian.

Brian, thanks for all the firsthand info on the Clark. Up till now, all the info I've come across is second hand or guys telling me, "I've heard". You mentioned next time around using an 8" twist instead of a 10". That's what I had in mind because I want to use the heavier bullets. I take it the accuracy with the heavier bullets wasn't all that hot with the 10" twist? Thanks.
Craig

Craigster,
I had a 1 in 10 twist barrel, because the only suitable bullet available in Australia in 1988, was either the 68 grain Hornady or 69 grain Sierra.

I tested and chronographed the Hornady 75 grain Amax, and Sierra 80 grain HPBT when they became available in the late 90's. I discovered that the 1 in 10 twist would not stabilise the 75 and 80 grain bullets, as they keyholed into the target at 100 yards. Regards, Brian.

I have built several .224 Plummers for customers and owned one my self. With a 26" barrel and 50 grains of 4064 the velosity was 4579 F.P.S. 55 grain bullets with 49 grains of powder ran around 100 FPS slower. The best three shot 100 yard groups I shot with the rifle measured .368" for extreem spread. and that was after over 1,000 rounds. Usually I could shoot around .400s extreem spread with the gun. By the way you would not believe what that 55 grain bullet at over 4400 does to a coyote!!

THANK YOU JUDSON FOR STAYING WITH THE TOPIC AND GETTING ME SOME INFO. WAS I CORRECT IN THINKING THE PLUMMER IS A 224 TTH THAT IS IMPROVED? WHAT KIND OF VELOCITY WOULD I EXPECT FROM A 75 GRAIN V MAX AND WHAT TWIST WOULD YOU RECOMEND FOR THE 75 GRAIN AND BELOW BULLETS?

From what I have learned, the Plummer was designed to throw 70 grain bullets at around 4100 fps and be used for deer and pronhorn, stuff like that. When it was developed neither the right powder or bullets were available so it sort of fadded into the weeds. Let me check on the twist you need but you will probably find that it will be slower then you think. When you get up into the hyper velosity cartridges things change. For example if you want the 7mm Rem Ultra to work as it should with lighter bullets like 140 grain then you need a 1-11" twist not the normal one in nine, you also want a 29" barrel. You would think that Remington would know this but it is obvious they do not. With a set up like this the 7 Ultra will push 140 grain slugs up to 3700 fps and when set up right shoot under 1/2" at 100 yards.
The plummers I have built used a 1/10 twist but tho it sounds strange I think you would want around 1/11" let me do some checking. You should be able to get those 75 grain slugs going about 4000 fps, if they hold togther.

MUCHO GRACIAS JUDSON. THAT WAS THE KIND OF INFO I WAS LOOKING FOR. I WOULD GREATLY APPRECIATE THE TWIST RATIO WHEN YOU GET A CHANCE, AS I PLAN ON SEEING IF I CAN GET ONE OF THESE BAD BOYS MADE. THANKS AGAIN.

If you want a Plummer give me a call. I have the reamer, loading info and all that stuff. # 207-938-3595 building custom rifles is what I do for a living. As for twist, I would go with a 1 in 12 for the heavy bullets. I have not tried bullets as heavy as you mentioned but that rate of twist should work. I found that IMR 4064 worked best with the 50 and 55 grain bullets. It does not come close to filling the case and untill a friend of mine and an avid wildcatter convinced me to try it I would never thought a powder that fast would work. I believe for your bullet weight it would be too fast so I will talk with the guy and see what he thinks. I used 50 grains of the stuff with the 50 grain slugs and either 48 or 49 grains with the 55 grain bullets. On all my loads for the Plummer I ran CCI mag primers for the best groups.

JUDSON I WAS ALWAYS UNDER THE IMPRESSION THAT FOR ABOVE 70 GRAIN GULLETS IN 224 YOU WOULD WANT A 1 IN 8 OR 9 TWIST AND FOR 70 GRAIN YOU WOULD WANT A 1 IN 10 TO STABILIZE THE BULLET. ON THE SHILEN BARRELS WEBPAGE THEY STATE PRETTY MUCH TO THE SAME EFFECT. THEY DO NOT GIVE VELOCITIES HOWEVER. WILL THE 1 IN 12 STABILIZE THE 75 GRAIN BULLETS AT THE PLUMMERS VELOCITY, OR BECAUSE OF THE VELOCITY DOES IT REQUIRE IT. BY THE WAY, THE BARREL WOULD BE A SHILEN 28" WITH A BROWNING A BOLT ACTION.

I talked with a friend of mine today, he is the one who got me into wildcats and is a walking talking reloading manual. He said that he thought you would be better off with a 1 in 9 inch twist even with the velosity you will be able to get. ( 4000 fps or close to that) As for powder he thinks that IMR 4831 should be about the right burn rate, you will want around a 26" barrel or longer, no more then 29" but from 26" on you will not gain all that much. However shorter then 26" you will loose alot!
I question your choice of actions to use as the A Bolt is strong but not built for longevity. With hot loads your head space will increase rapidly. From what I have read and experanced with this action this seems to be true.

THANKS FOR THE INFO ON THE A BOLT ACTION. I ALSO HAVE AT MY DISPOSAL A MAUSER 98 ACTION, OR A WEATHERBY ACTION FROM A VANGAURD, OR A RUGER M77 MARK 11. WHICHEVER ONE YOU SUGGEST, BUT I WILL BE PLAYING A LOT SO SOME OF THE LOADS WILL BE HOT TO A CERTAIN DEGREE. I DO KNOW THAT THE RUGER ACTION IS PRETTY RELIABLE FOR IT IS CURRENTLY ON A SWIFT AND SOME PRETTY HOT LOADS HAVE GONE THROUGH IT.

P.S. MAY I SAY THAT THIS IS ONE AWESOME WEBSITE WHERE PEOPLE CAN COMMUNICATE ON A HOBBIE(OR BURNING PASSION AS MY EX WIFE CALLED IT) AND TRADE INFO. I AM SOMEWHAT NEW TO RELOADING (2 YEARS) AND THE MOST IMPORTANT THING I HAVE LEARNED IS YOU CAN NEVER LEARN TO MUCH AND WILL NEVER LEARN IT ALL. THANK EVERYONE AGAIN.

I would go with the Ruger since here you are talking about just rebarreling. The Mauser if made by a good company is great but if it is military then alot of work has to done to it before you can scope it up. If the Mauser is a comercial action or the action already re worked then which action to use is up to you. One thing going for the Mauser is all the goodies available for them such as Kiplinger single set triggers, bolt shrouds and all sorts of other stuff.
If you decide to build a Plummer let me know, I have all sorts of loading info including fire forming loads. Also there are a couple of tricks that make firing forming easier. Feel free to call me with any questions the # is 207-938-3595.