HillbillyLongRifle
Gold $$ Contributor
.300 runout?
Wow thats insane!
Wow thats insane!
A funny story about barrel runout.
- Thread starter Alex Wheeler
- Start date
ELR LVR
Silver $$ Contributor
So it's like a gain twist, but different
seb
Site $$ Sponsor
Quoted from Alex "I explained he would have elevation issues. I clock the barrels up, so it would effect elevation, but not windage. Dialing only one end takes that curve out of the picture, so the throat looked just as centered as any other barrel. The curve was very obvious to the eye, it was a consistent curve like a banana for those interested."
In case I ran out elevation next time, I would ask someone big/heavy to step on my barrel to make a really good-consistent curve. Still not enough? I could probably ask 2 more! No need to change scope / base.
From issue to solution + advantage, thanks for the idea Alex! And I will remember the number 0.3"
In case I ran out elevation next time, I would ask someone big/heavy to step on my barrel to make a really good-consistent curve. Still not enough? I could probably ask 2 more! No need to change scope / base.
From issue to solution + advantage, thanks for the idea Alex! And I will remember the number 0.3"
xr650rRider
Silver $$ Contributor
urbanrifleman
Site $$ Sponsor
All barrels should be contoured between centers to center up the holes, I think. So, to that end the unturned blank has to start at some larger diameter. My blanks all start at 1.25" so I don't sell a 1.25" straight. I always insist on a bit of taper to the muzzle end so I can clean up the centers.
As an aside, I've heard some truly ignorant stuff. I guess I'll just keep it those encounters to myself. I'll just say this... most people have zero knowledge of barrels and how they are made. Why they work, or don't. And there are even more that claim they do, and are full of beans.
This thread is interesting, it has made me feel very lucky. I carry a rifle, and I shoot it, it sits in a cabinet until I need it, I pull it out check the bore for blockage run a dry patch and shoot it. The bullet goes where I intended, I'm happy. I don't worry about all this stuff I have a smith that does that for me!
The difficulty today is not finding a rifle that shoots good, it's finding a smith that makes a rifle that shoots good.
America is a great place to be a shooter, I wanted an everyday rifle, I wanted an AR for its utility, and I got one. It shoots well enough that I can properly map the elevation marks on the reticle and use the BDC as a reasonable range estimator. It can sit in the cabinet for months and when I pull it out and shoot it the bullet goes where I intended it to go. Rinse and repeat, all thanks to competitors who tirelessly work on wildcat cartridges, companies that standardize wildcats, companies that build rifles and parts and gunsmiths that work toward perfection. All for me! I'm very lucky!! I live in The United States of America!!!
WSnyder
Silver $$ Contributor
Finished blanks are concentric (bore to OD) at the breech and muzzle. You'll see the muzzle runout discussed in this thread when setting up for chambering when you dial in solely from the breech end, i.e., at the throat and forward of the throat and let the muzzle go where it may. The manufacturer will never see this in the production of the barrel.
Note: When you significantly shorten a blank at the muzzle end it is very common to see an offset bore (not concentric to the OD).
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A couple years ago I chambered two 7 PRCs at the shop. These rifles were for the Nightforce 2000 yd shoot for two members of our company. These rifles had the same chassis, scopes, and barrels.
The barrels were not only from the same lot of steel, they were from the same rod of steel, blanks #2 and #3. They were drilled, reamed, rifled, contoured, and lapped by the same guy(s).
When I chambered them I cut the chambers the same, to the point where the brass was interchangeable between the two rifles.
One barrel had .030" of run out when dialed at the throat and the breech, the other had .060". I did not tell the shooters which was which. One barrel shot everything well, the other was fussier and took much more effort.
The better shooting blank was the one with more runout.
The barrels were not only from the same lot of steel, they were from the same rod of steel, blanks #2 and #3. They were drilled, reamed, rifled, contoured, and lapped by the same guy(s).
When I chambered them I cut the chambers the same, to the point where the brass was interchangeable between the two rifles.
One barrel had .030" of run out when dialed at the throat and the breech, the other had .060". I did not tell the shooters which was which. One barrel shot everything well, the other was fussier and took much more effort.
The better shooting blank was the one with more runout.
FireMedic
Silver $$ Contributor
I have never seen a barrel that was curved like a banana. To me, bores seem to wonder like a helix. Most of the time they will be worse at one end than the other.
.300 of banana shaped runout should have been very obvious to the barrel maker. I’m not sure how that would make it out of the shop. Maybe the barrel was bent during shipping?
.300 of banana shaped runout should have been very obvious to the barrel maker. I’m not sure how that would make it out of the shop. Maybe the barrel was bent during shipping?
urbanrifleman
Site $$ Sponsor
It is a helix. Drills make helix shaped holes.
The center of the barrel relative to the outside changes depending on where you cut it.
FireMedic
Silver $$ Contributor
Sure but I said bore, not the outside of the barrel. Thats what we are talking about here.
I believe Alex was talking about the same thing (bore) runout, and he said it was banana shaped not a helix.
urbanrifleman
Site $$ Sponsor
Stan Taylor posted a bunch of great bore photos showing the helix.
Some barrel makers rough contour before drilling the blank. Then the barrel is drilled from the muzzle end, centering the bore on the muzzle end. After being rifled the barrel is final contoured.
The was a guy that wrote for PRECISION SHOOTING that sent a few barrels off to a company and they mapped the inside of the bore of a rifle barrel. Barrel straightness and any changes in bore diameter.
It was interesting to see the variation in the bore. It didn’t change the way it shot or help predict if you had the next record breaker or not.
Hal
The was a guy that wrote for PRECISION SHOOTING that sent a few barrels off to a company and they mapped the inside of the bore of a rifle barrel. Barrel straightness and any changes in bore diameter.
It was interesting to see the variation in the bore. It didn’t change the way it shot or help predict if you had the next record breaker or not.
Hal
Northridge
Gold $$ Contributor
Second worst barrel I ever fit from a run out stand point went on my “ugly” gun in 2017 best agging for ten shots I ever had… I have personally favored barrels even Pryor to that one as a result of casual studies over time suggesting to park my concerns in different items.. it’s all interesting
Shawn Williams
Shawn Williams
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