Gunsmithing Krieger barrel twist rate stamps????

[dondlhmn]

I've got a 6.5mm Krieger rifled blank that is stamped on the butt end with the rifling land diameter, the rifling groove diameter, the letters "SS" , the brand "Krieger" and what is definitely an "8"....not eight POINT anything...no 8.25, no 8.5 no 8.ANYTHING, but this barrel is what they sent me when I ordered a 8.5 twist. So...how finely does Krieger measure and mard the twist on the butt end (chamber end) of their rifled barrel blanks? I do not have any experience with this barrel marking thing with barrels from Krieger, yet my 'smith says the barrel is definitely STAMPED as if it were a 1 turn in 8 inch twist. I have pretty carefully checked the barrel's twist rate and it appears to me and others that have looked at it to be somewhat over an 8, but not a 8.5 twist.....more like 8.28 or there abouts.

So...my question to all of you is: What is the interval with which Krieger marks their barrels? Do they get as accurate as a tenth of an inch? Half an inch? A quarter of an inch? Would the twist be quite accurately measured and accurately stamped on the butt end down to a tenth of an inch? Or is it just kind of close?

I really want to hear what experiences/knowledge any of you have with this. Please either PM me or reply to me at [email protected].

THANKS A BUNCH!!!

 

[Temp9]

Did you call Krieger?

 

[dondlhmn]

Did you call Krieger?

No..I haven't called Krieger yet...it is Sunday today and they are closed, but you can bet that I will be on the phone in the AM to find out how they do the measuring/marking and to what degree they carry the marking (down to .1"? maybe .250"?...what?). As is common knowledge, faster is better than slower, so I will likely just go ahead and use this barrel for the 6.5 X 55 Swede build I have in mind and it will likely shoot the heavier bullets better than what I really need (planning on using that gun with 120-123-130 grain bullets), but now my curiosity is up and I want to know how they do it so I will know for future reference. The funny thing is that the barrel (which I got my hands on yesterday (Saturday) is marked with an "8", but that seems to be only "close"...NOT the sort of precision I expect from Krieger. Hmmmmmm......ANYWAY, for the time being... back to the Chiefs/Broncos game!

 

[Edds]

I have a Krieger 6.5mm 7.5" twist barrel. I checked the twist rate with a cleaning rod and patch. I believe it is exactly 7.5".

 

[Bugholes]

I would assume that they would mark the barrel to the 10th of an inch. The gears in the riflers will work out to a much longer and more complicated number, but there's no need to carry out that number beyond a tenth on the breech. Use a tighter fitting patch when you check twist rate with the patch method. Also realize there is a man stamping the barrel, therefore sometimes things don't go right. I've seen some goofy stuff stamped on the end of a barrel- Wrong bore size, wrong material stamp, wrong twist rate, etc. Either 8 or 8.5tw will work for the swede so you won't have any trouble either way. Beats waiting another 11 months

 

[dondlhmn]

I would assume that they would mark the barrel to the 10th of an inch. The gears in the riflers will work out to a much longer and more complicated number, but there's no need to carry out that number beyond a tenth on the breech. Use a tighter fitting patch when you check twist rate with the patch method. Also realize there is a man stamping the barrel, therefore sometimes things don't go right. I've seen some goofy stuff stamped on the end of a barrel- Wrong bore size, wrong material stamp, wrong twist rate, etc. Either 8 or 8.5tw will work for the swede so you won't have any trouble either way. Beats waiting another 11 months

Yeah...assumptions are easy to make and I would, like you, hope that any good barrel maker (particularly an aftermarket maker, most of whom charge a stiff price for their barrels) would be conscientious enough to be sure that the twist rates were accurately measured and then accurately marked. And, as the old joke goes..."Then the trouble started." Some of the reasons for barrel twist questions and problems (particularly later in the barrel's life) are:

(1) Many, many barrels made by major gun manufacturers are not marked with twist anywhere on the barrel by the time it gets to the end user. To make matters worse, a lot of manufacturers have produced the same caliber barrels in various twists....still not marked anywhere.

(2) Custom barrel manufacturers can and will produce pretty much any barrel a person wants with pretty much any twist rate a guy can dream up.

(3) Custom barrels are usually marked, but sometimes not or (as "bugholes" pointed out above) not marked correctly due to good old human error either in the measuring or the marking.

(4) Even IF the barrel was accurately measured and then accurately marked on the butt end, that piece is pretty much always cut off when the barrel is chambered, so a guy looking at the barrel later (or even a complete rifle) has no way to know what it is short of checking/measuring the twist rate.

(5) When measuring a barrel's twist, errors can creep in due to several problems:

(5) (A) The reference mark placed on the small diameter rod is hard to clearly and plainly index as it comes around due to the small diameter of the rod, resulting in a maybe not too accurate measurement of revolutions. This can be solved by firmly attaching/fastening some kind of a pointer with a larger "radius" to the small diameter rod. This results in a longer travel of the end of the pointer and makes it way easier to see if the thing went all the way around once...EXACTLY...or not all the way around. Another thing that can be done is to see that the pointer goes around EXACTLY twice and then taking the measurement of how far the rod traveled, but then halving that number to get the twist rate. Most twist rates are in pretty simple numbers, but I have seen them turn out to be not all that simple, like 7.77 and so forth. Apparently SOMEONE, SOMETIME thought there was a good reason for whatever twist rate...who knows??

(5) (B) A possibly not very precise fit between the device used in the bore to turn the rod, resulting in slippage and, therefore, not an accurate number of turns imparted to the rod as the device is moved along the bore.

(5) (C) Joints in the rod (if there are any) not being TIGHT enough so that they are solid and, therefore, do not impart the full turn(s) to the next piece of rod in line.

(5) (D) Inaccurate measurement techniques.

So, in the interest of gaining some knowledge on this subject and NOT so much as to pick nits, I want to learn more about the hows and whys barrel manufacturers measure and mark their barrels. It seems that there is always someone asking me (WHY ME??? ) some kind of a question about twist rates and I want to think that I am telling them the right thing, so the only way to be sure about that is to EDUMAKATE myself. Granted, if a twist rate is a couple of decimal points faster than the "advertised" rate, the barrel will likely not be any less accurate in the ballistics department, but if it happens to be wrong in the other direction (especially HUGELY wrong), things can go to hell in a hand basket pretty quickly. Not to mention that if you don't REALLY know what you are starting a build out with, you just may waste a bunch of time and/or money on a build that winds up being "mysteriously" not so accurate. I hate it when that happens!! Another reason I want to know is that when I am helping/advising someone on developing a load, having a good, solid idea of the twist rate of their barrel can be pretty handy and save some time wasted exploring in the wrong direction, eh? (No, I am NOT Canadian).

PS....also, my buddies call me ANAL for some danged reason....go figure!!

 

[Edds]

What did you find out when you called Krieger?

 

[dondlhmn]

What did you find out when you called Krieger?

Well, I had kind of an interesting conversation with one if their inspectors (don't remember the guy's name..) about barrel markings, particularly markings on the barrels they produce for their distributors and how barrels are machined and marked. My particular barrel was purchased from Bruno's Shooter Supply in Phoenix. The barrel I have, ordered from Krieger directly would be an 11 MONTH wait, but Brunos is one of Krieger's biggest distributors (I think Bruno's cust service guy told me they order 3000 barrels a year from Krieger) so I got it in like 4 days. Anyway, Krieger's guy told me that their barrels are marked in .5 inch intervals.... 6, 6.5, 7, 7.5, 8, 8.5, etc. which are about the only ones they produce unless it is pretty much a special production barrel. There are a few calibers that are commonly ordered/produced in what the rest of us might consider to be odd twists like 9.35 (for .338 cal), but I believe he said they get marked that way. He did say, however that my barrel with the "8" stamped on the butt end would be pretty much a collector's item, as it measured out (REPEATEDLY by me AND a buddy (I had my buddy do it just to be sure I wasn't hallucinating or something)) to be 8.5 twist. He had no specific explanation as to how mine could be stamped 8 but be 8.5 twist. However, we talked about how their rifling machines are set up to produce a certain twist, then the first barrel is checked. If it is in spec, they basically let it rip and check only SOME barrels out of the run of barrels it produces, once it is set up and it passes muster on specs of the barrels coming off. Then we talked about how manufacturing specs can "stack up" in any direction and he pointed out that, unlikely though it may be, it IS POSSIBLE that somewhere along the run a barrel COULD come off the machine that COULD be that far out. Personally, I BELIEVE that the barrel I had was simply mis-stamped by whoever was doing the stamping that day, as it would have to have been 1 barrel in zillions to be right on 8.5. The thing that makes me wonder is how it got a Bruno's Sticker on it that indicated 8.5. With that many barrels coming in, I can't believe that they check EVERY ONE...but maybe...? I can see how, when an order comes in for a barrel in 8 twist Like mine), the person filling the orders likely would just read the butt ends and pull the one with an 8 on it since they likely are stacked with the numbers on the butt facing the picker and he/she never would really even look at the sticker on the side.

Anyway, I called Brunos and spoke with a fellow named Daniel working the customer service line and after I told him the story, he said I should jsut sent the barrel I had back to them and they would pay the freight and send me a replacement. GREAT customer service to fix the boo-boo and Daniel was VERY helpful. The guy at Krieger also offered to take the barrel back, but that conversation was pretty much stopped by me when I told him that Bruno's was going to take care of it. I will let Bruno's and Krieger to deal with each other and figure out hot that barrel got marked/shipped like it did.

So...to make a long story short, I will wind up with a barrel that is what I originally ordered at no extra shipping cost to me......only cost to me will be a bit of time for the round trip shipping. Either Bruno's OR Krieger would have covered it for me, including freight. The only thing I am out is some time wondering about the whole thing and learning something.......well, it does set the build back maybe two weeks, but that is no big deal for me.

 

[aagifford]

Pic I found shows a Krieger with 7.7 stamped on it. A 12 has 12 stamped on it. An 11 has 11 stamped on it. So, it seems that they stamped an 8 because it is 8.

My Krieger 12 twist was stamped 12, and measured 12. If you want to measure it yourself accurately, I would suggest the following:
Clamp the barrel.
Obtain a cleaning rod with a patch, tighten any joints.
Insert cleaning rod/patch into barrel and engage into the rifling.
Clamp a visual rotation indicator onto the rod that is perpendicular to the rod. For instance, a wooden ruler, with a screw and a fender washer to clamp the ruler onto the rod. Align said indicator to something either vertical or horizontal (your choice) as you sight down the barrel. Push cleaning rod/patch into barrel until said indicator aligns to your sighting object. Make sure that the indicator it is far enough to get to at least 1 full turn, preferably two full turns and adjust as necessary to achieve this. Make sure the indicator is slip resistant.
Mark the starting position with a razor. Scratch the cleaning rod to do this. You can apply marker or dykem to the cleaning rod if you feel prior to making this first mark. Even tape if you want to not scratch the rod.
Push the assembly of cleaning rod/patch/sighting indicator until you get either 1 or 2 full turns, mark the rod again. You should quite easily achieve better than 1° accuracy on your rotation and better than 1/16" error on your distance.
Measure the distance between the 2 marks and find your twist.

I just saw the info you posted, very interesting! Sounds like your assessment that it was likely mis-stamped is the most likely.

 

[dondlhmn]

I was chatting with Daniel at Bruno's this AM and it appears that the "3000" barrels I had stuck in my mind was the right number, but was actually the number of barrels they have on back order right now with Krieger. He says that they put 6000 to 7000 KRIEGER BARRELS A YEAR through Bruno's and that Bruno's is Kriegers biggest distributor!!!