Ruger MKIII rifling

piasashooter · Post by **piasashooter** » Wed Apr 18, 2012 1:17 pm

I was cleaning the bore of my new MKIII the other day and when looking at the bore with a light I noticed one of the lands near the crown did not look quite right. After looking at it with a jewelers loupe, I could see that on one side of one of the lands, the land was marred, or rounded over, for about 1/8 of an inch, maybe less. I could clearly see for the short length that it was not a nice squared, 90 degree edge like the rest of the land. I have shot the gun, and off hand it seemed to shoot as good as I could perform. I was wondering if this could have much effect on the accuracy of the gun, I guess I would have to ransom rest it to really find out, it was just disappointing to see this.

Hakaman · Post by **Hakaman** » Wed Apr 18, 2012 2:11 pm

I purchased a S&W m&p Pro 9mm and the rifling was messed up near the muzzle end. The cutting tool used to rifle the barrel was probably defective. S&W repaired it rapidly. My own personal estimate on your gun is that only a sharpshooter would see any accuracy issues? Just the same, I would definitely send it back to Ruger to have them replace the barrel. You didn't mention how long you have had the gun? or how many rounds have been fired through it?
Haka

piasashooter · Post by **piasashooter** » Thu Apr 19, 2012 1:41 am

The gun is almost brand new, it has about 100 rounds through it. I just had deal with sending a gun back to Ruger, and from what I learned doing that, I doubt they will want to replace the barrel. I had to fight to get them to replace my previous gun. If they test fire the gun and it shoots reliably, and there is no major problem with the accuracy, it's good to them. At least that's what they did with me before, then I had to stress how disappointed I was, to get them to do what was right. Not to mention they told me 10-15 business days, for the turn around time, then it took 35 business days. And if they determine that there is nothing wrong with the gun, they charge you for the shipping both ways, about $120.00.

Post by **Bullseye** » Thu Apr 19, 2012 6:43 am

Likely what you're seeing are marks from the pilot bushing on the crowning cutter. I have seen some pretty heavy marks from these over the years on Ruger .22 Autos with little if any detriment to accuracy. Some extending nearly one full inch down into the barrel's rifling grooves. The most important part of that end of the barrel is the actual crown itself. If it is dinged or worn then the bullet will be disrupted in flight when exiting the barrel by a inconsistent distribution of gasses and may wobble in flight causing erratic trajectory errors. If you've grouping around 1-2 inches at 25 yards that is acceptable for factory standards.

R,
Bullseye

piasashooter · Post by **piasashooter** » Thu Apr 19, 2012 1:44 pm

Thanks Bullseye, that was pretty much exactly what I wanted to know. The crown itself looks pretty good, it was just the land that showed unusual marks. The gun seemed to shot accurate at 50 feet, and probably would shoot up to there standards at 25 yards, I was more worried would it be effected at 50 yards, but until I have either of my rugers ransom rested, I won't really know how they shoot a 50 yards. I think if it really became a problem to me, it wouldn't be to much work to have my gunsmith recess the crown back just a little farther than it is, to get rid of the short length the land is marked. Also while I'm writing, in your experience with ruger .22's, have you ever found them to benefit from being re-crowned, not fixing a damaged crown, just trying to put a better one on, than from the factory. I only ask because I hear all sorts of things about crowns, and how people swear by different types of crowns, and how they improved accuracy. I'm sure there are people out there who are talking out of there a**, but I thought I would ask you since I trust your judgment. Again, thanks.

Post by **Bullseye** » Thu Apr 19, 2012 10:29 pm

Recrowning a barrel with a perfectly good crown could generally, in a best case, improve accuracy by about 10%. That is really not much improvement in expected accuracy. That means if you're presently grouping at a 1" diameter circle you could at best see a .1" shrink in the diameter with a new target crown. There's not enough justification to go through the process of recrowning a good factory barrel for that little of potential improvement.

R,
Bullseye

piasashooter · Post by **piasashooter** » Sun Apr 22, 2012 1:29 pm

I was thinking that there wouldn't be a whole lot of room for improvement on a good factory crown, but was curious and figured I would ask. Thanks again for answering my questions.