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Discussion Starter · #1 · (Edited)
Sorry, that's STAINLESS

Anyone have accuracy problems with those stainless steel replacement barrels? I was having a very depressing shoot with a recently acquired Russian IJ-70 Mak. I couldn't hit anything. It was shooting way to the right, and low at about fifteen yards. I adjusted the rear sight all the way to the side and it helped a little. Not much.
 

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Stainless Steel barrel

Did you just buy this from a guy on the net. I saw one advertised just like that and the seller included the original barrel and suggested re changing it. James
 

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Discussion Starter · #3 ·
Did you just buy this from a guy on the net. I saw one advertised just like that and the seller included the original barrel and suggested re changing it. James
No, I got this a while ago. It had a .380 barrel in it when the previous owner bought it. he changed it back to 9x18, but didn't use in an original barrel.
 

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I swapped a barrel out for a stainless, ported barrel in an IJ. Shoots low/left now. Will likely be swapping the barrel back, but I'm going to give it a couple more chances at the range first. THe shots are consistent, but all go low/left. I can compensate by aiming high/right and get a good 10 ring area group, but I don't want to have to aim where it's not going to hit to make it hit where I'm not aiming.
 

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I swapped a barrel out for a stainless, ported barrel in an IJ. Shoots low/left now. Will likely be swapping the barrel back, but I'm going to give it a couple more chances at the range first. THe shots are consistent, but all go low/left. I can compensate by aiming high/right and get a good 10 ring area group, but I don't want to have to aim where it's not going to hit to make it hit where I'm not aiming.
Sometimes this can be caused by not using even pressure when removing the old barrel with a barrel press or other means. If the Barrel hood gets tweaked slightly, when the new barrel is installed, it will be pointing slightly off center. An easy way to tell if this is happenning is to look at the hole in the slide the barrel protrudes from, see if there is an even amount of gap all the way around the barrel. If not, you may be able to adjust it slightly by fixing the frame, just under the barrel hood in a vise, and use a 12" or so long tube to tweak the barrel back into alignment. Just make sure to go slow, and use light pressure. You want to move the barrel in the direction of correction. A change of .001 will result in about a 1/4" change in point of Impact at 25 yds. So if your barrel is shooting 2 1/2" low and 3" left, than you would move the barrel .0085 up and .009 right. Heating the barrel hood is NOT an option, as the heat treating is critical in this area. Oh yeah, if you get too heavy handed with this option, you will crack the barrel hood, and ruin the frame.


-George
 

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Discussion Starter · #6 ·
The barrel looks pretty well centered in the slide. Not to hijack my own thread, but how much heat is bad for the barrel hood?
 

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The frame is a steel alloy, and likely a high carbon variant, additions of substitutional elements could only be assessed by elemental analysis testing. I would speculate that the billet frame is machined from is forged, quenched and tempered. Ideally, a cycle of austenitization, water quench, and temper with the metal blank near net shape gives improved geometric stability after machining.

Being a carbon steel alloy, there are generalizations that can be made as to how hot and how long it may be heated, without affecting the desired design properties. One point of reference can be that if the metal has even the faintest red glow, red glow in a dark room is detected at about 725 F, it is likely heated beyond the point of maintaining confident control of metallurgical properties, For This Specific Context. Nothing is absolute here, because a range of possible primary processing for production results in a range of material response to heat and deformation.

For the sake if making fine deformations to re-align the barrel, my opinion is that no heat need be applied, as at the relative yield strength levels for this material in the range of reasonable temperatures (I suggest to 400 F max for any length of time) does not change much, and hot metal is harder to handle. Any cold tweaking should be executed in a very progressive and contolled fashion. Experience may give confidence, but does not change the methodology.

That said, I am looking to the future to at some time changing out barrels, either in a Mak or in a Feg (aluminum! frame), and i plan to heat the barrel hood (centered along a line at 12 o'clock) just before clamp force is applied. This is simply an attempt to get the two parts to release as easily as possible with the least amount of release stress on the barrel hood. The technique requires that the barrel be not similarly heated and I'm thinking of packing it with dry ice. The heat source will be a propane torch, with the inner bright blue flame never getting near the metal. Temperature control could be verified using a 350 F temp-stick as can be gotten from a welding supply.
 

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Discussion Starter · #8 ·
Well that's certainly a mouthful pbwe! I see what you're saying. The reason I asked is that I changed out a mak barrel using a blow torch to the barrel hood and ice (not dry) on the barrel to help get it broken loose. I don't think I ever got it near 400-degrees, certainly never got it red at all. I just don't need the barrel driven into my left eye because I did a no-no and weakened the hood.
 

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"I just don't need the barrel driven into my left eye because I did a no-no and weakened the hood."

There is that pressed retaining pin below the barrel.

I guess dry ice would be hubris.
 
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