I'm looking at getting a 240 Gibbs barrel to shoot the heavies fast, and was wondering if any certain barrels would last longer than others, hopefully getting me 1500+ rounds of barrel life. A 32" Shilen Match is only $279.

Another question, does anyone have experience with "ratchet rifling"?

Thanks,
Tyler

Hottt 6mm's are throat eaters. 1,500 may sound achievable but doubt that it is. Some hottt 6mm's are washed out in 600 rds as far as benchrest type accuracy. 6.5's tend to last a little longer. I would think the cut rifled Krieger would be your best bet as far as trying to get that life. I compete in NRA Highpower and the Kriegers get a little more long range life than Douglas, Shilen, Wilson etc. Is chromelining an option? Very little accuracy lost in todays chromelining if it was a premium and I mean very premium barrel to start with.

I have no clue as to chromelining. Where is this done, what does it cost, and what effect does it have?

The most important thing is to keep it clean and don't let it get hot. As stated above a cut rifled barrel should last a little longer, you simply can't get the groove depth and definition with a button than you can with cut rifling.

WHo would you send a barrel to to get the bore plated? WHat type of accuracy degredation would you actually get?

I would get your barrel Melonited a.k.a. QPQ'd. It has been mentioned here a few times before and hope Our Resident Metal Exspurt (Mete) will see this thread and give us his opinion on extending barrel life. He says Melonite does live up to the lofty sales pitch. It is actually a surface treatment of the steel that makes it harder. Butch Lambert has had great success with a Melonited benchrest barrel that gave him excellent and extended usable life.

I would think the little Gibbs would be brutal on a barrel.

Cut rifled barrels are generally thought to last longer than buttoned. I don't know if chrome moly or stainless makes a difference.

If you are doing your own chambering work, I'd recommend specifying the breech end be 4" at the large diameter instead of the more typical 2". This will allow you to set back the barrel by cutting off two inches and rechambering. You'll extend the barrel life a bit, but it doesn't make sense to do this if you are paying someone to chamber it.

In the end, I think you will be hard pressed to get 1500 rounds out of that caliber even with a setback.

Shilen uses a shallower riflng than some makers to minimize barrel stress when the button is pulled and/or bullet distortion to enhance accuracy. So theoretically that design would wash the throat sooner.

I love Shilen barrels but none of mine are in hot rod calibers so I can't say it happened to me. A friend built a 270 Wby with one and had some pretty rapid throat advancement.

Lothar Walther stainless barrels have a reputation for long throat life because of the alloy they use. Again, my LW barreled rifles are pretty pedestrian catridges so I can't compare.

The only hot rod barrel I have any long service in is a Kreiger 220 Swift and throat life has been excellent; much better than the original factory Savage barrel.

I just had a 300 Wby Shilen barrel QPQ'd but don't have enough time on it to say one way or the other.

What did getting the barrel "QPQ"ed cost?

quote:

Originally posted by tiggertate:
I just had a 300 Wby Shilen barrel PQP'd but don't have enough time on it to say one way or the other.

Who did you get to do it? I have a pistol I need to get treated.

Also, is yoour .300 a SS or CM barrel? I have wondered how feasable it would be to have a CM barrem Melonited and then sand the outer surface down to bare metal so it could be rust blued. THat would give me a hard bore and still have a proper finish for a high end custom rifle. For something fairly hot that is in a custom stocked rifle with tight wood to metal fit, extending the barrel life makes a lot of sense.

I had the whole rifle done by Tip Burns and it looks like he did some metal prep too. Including shipping and insurance it ran $304.00 and I suppose a barrel alone would be somewhat cheaper.

Mark, mine was CM. I'm about to send in a stainless barrel for the first time. I don't know why that wouldn't work. As I understand it the treatment is only a few thous into the metal surface. I'll post a picture when I get home.

Forgot to add that Tip's price for pistols is the same; $249.95 plus shipping and ins. Tip is in Canyon Lake Texas Burns Gun Repair

He has done one or two for other posters and they were happy with the result as well.

Anyone tried "gun juice"? I see lots of positive reviews online.

+1 on the QPQ.... when tip built my .264 win mag last year, the finish was QPQ.... very nice soft luster, and will not scratch....

quote:

I would get your barrel Melonited a.k.a. QPQ'd. It has been mentioned here a few times before and hope Our Resident Metal Exspurt (Mete) will see this thread and give us his opinion on extending barrel life. He says Melonite does live up to the lofty sales pitch. It is actually a surface treatment of the steel that makes it harder. Butch Lambert has had great success with a Melonited benchrest barrel that gave him excellent and extended usable life.

Tip Burns showed me a QPQ'd barrel and handed me a file and said "try to cut it", it wouldn't make a mark on the barrel.

Friends-

What does the QPQ treatment look like on a firearm? Does it look blued?

It is blacker than hot bluing. Closer to a deep rust blue but still a little more black. I got home too late to play last night; I'll try to get a picture up soon.

quote:

I'm looking at getting a 240 Gibbs barrel to shoot the heavies fast, and was wondering if any certain barrels would last longer than others, hopefully getting me 1500+ rounds of barrel life

Don't know what you want to shoot or how fast but 240 Gibbs data shows 105s at 3250 from a 26". I built my own version using my blown out 280 case years ago. Burned a lot of powder and the barrel to just barely beat a 6mm. A 6mm 6mmAI or 240Wby is more powder than you can really use.

I spoke to a guy on LRH and he said he was shooting 107 SMK's at 3500 out of a 26" barrel?

I'm wanting a minimum recoil cartridge (braked) that is supersonic to a mile.

quote:

he was shooting 107 SMK's at 3500 out of a 26" barrel

Well I couldn't get close and neither did Rocky Gibbs.

You might want to run your numbers. I calculate that the 107 needs to have a velocity of around 3900 to be supersonic at a mile.

I was planning on the 115 DTACS around 3400 fps, .595 BC. 30" barrel as well.

My velocity in a 26 and a 105 was closer to 3250. I have a couple extra grains capacity over a Gibbs. I never tried a 115. I do know that my throat was gone after just a few 100 shots.

Best of luck but I have serious doubts. Keep us posted.

I can get over 3250 fps from my 6mm Ackley with 46 grains IMR 4831 and 105 Amaxes and a lot less capacity and a 26" barrel.

Your velocity seems way lower than I would expect.

Like I said I just burned a lot more powder to get basically the same velocity of a 6mm or 6mmAI. I hope you get the speed you want. Your 6mmAI velocity is already what Nosler posts for the 240Wby. Looking at the Hodgdon sight they show 6-284 max H4831 as 48 and velocity of 2978. I don't have either case to measure but loadtech calls the 6-284 & 6mmAI to be within a gr in capacity. I would say you have a fast barrel. Using 1 for 4 a gibbs would give you 10% capacity over your AI so 2.5% or an extra 80fps. Loadtech calls 26-30" a gain of 80 So add 160 to your current 3250 you might get there. Like I said good luck but I'm a skeptic. Let us know.

Here is Rocky's data.

My 6mm AI has a case capacity of 59 grains (once fired), and the 240 Gibbs is 72 grains (once fired) according to the guy who is sending me some dummy rounds. That's around an 18% increase? So 4.5% increase in velocity, plus 80 fps you say for 4" of barrel. 3475 fps?

Oh well, theoretical thinking gets us nowhere, I'll post my results in the wildcat and smallbore forum.

Tyler I'm not argueing with the math. Just trying to share my experience with a case very similar to the Gibbs. To me your 6mmAI load is higher than expected velocity. In case you dont' have this link.
http://www.angelfire.com/sd/6mmackley/

Your load is 100-200FPS higher than posted loads with a 105-107. Not saying you aren't getting it just that it is higher than expected. Since you want an overbore. then there is the 6WSM. Gross capcity 78 vs 72 for the gibbs. http://www.realguns.com/archives/053.htm

Again I hope it works out for you.

I've been loading the 240 Gibbs for about 10 years now on a Interarms Mark X with an unknown make 26" barrel.

I have done 105's at 3400 but pressure was very excessive. Didn't even need a decapping pin to get the primers out.

I have found that this cartridge, while fun, requires the utmost in respect. In working up to max pressures there is a very fine line between its OK and "Whoa thats way too much".

A 30"+ barrel may get you what your after....maybe

I would use either a cut rifled barrel or a high quality hammer forged barrel.

I talked to a well known gunmaler at the Guild Show in Reno.

He said most American barrels are soft as butter, but Heym, and other German hammer forged barrels are very hard.