Why dial a rifle bore within .0001"

[Canadian Bushman]

I did a barlien 5r in .257 two days ago that was probably the best ive seen so far.

When i had about 4-6" dialed within a few tenths at the chamber end the muzzle was running just under .01. I was impressed. It dialed in very quick as well.

 

[Edd]

I misunderstood. I thought you literally meant the "ends" of the barrel.

Most reamers pilot about 2-3" in from the chamber end, but nonetheless this could be achieved all the same.

If you brought me a barrel and wanted it cut that way, i would do it. I dont pretend to know exactly what makes a barrel shoot. If its your barrel and your money you should get what you want.

If I could have it done that way, that is what I would want. That is if it wasn't set up in such a way that the barrel was being flexed to dial it in.

 

[Canadian Bushman]

If I could have it done that way, that is what I would want. That is if it wasn't set up in such a way that the barrel was being flexed to dial it in.

I dont think it would be a problem.

Im supposed to be doing a 6.5 barrel in a few weeks, i can try it, get back to you and let you know how the barrel ran.

 

[IdahoCTD]

I've done barrels dialing in both ends to run true and they shoot really well that way too. It's quicker to do most of the time as well. It makes more sense to me to do them by dialing in the chamber end only and the barrels I've done since changing to that method seem to shoot even better. It might only be marginally better but it does seem better on average.

 

[Edd]

I wish you guys would post pictures of your work.

 

[IdahoCTD]

I think Short Action Customs has a video on Youtube showing chambering the way we are referring to. If you looked around you could probably find a video of someone dialing in both ends of the barrel too. A picture is good but a video is better.

 

[Edd]

I think Short Action Customs has a video on Youtube showing chambering the way we are referring to. If you looked around you could probably find a video of someone dialing in both ends of the barrel too. A picture is good but a video is better.

I understand the way you are referring to and I've seen those videos by SAC. I have never seen a video showing the way I'm talking about. If you know of one, I would like to see it.

I would also like to see pictures that show the quality of your work.

 

[Canadian Bushman]

I got a 7rm getting cerakoted mon and a 257 wby im bedding right now (not going well) ill post pics next week.

 

[eddief]

Either method will produce equally accurate rifles, one is not better than the other.

 

[Edd]

First you have to define accurate. You could put the barrel on sideways and still have a rifle that would shoot a small group at a specific distance with the rifle in a specific position. The difference is when you start changing the distance to the target and the position of the rifle. Then there is the possibility of a much larger bullet impact area.

 

[J E Custom]

I guess the point is......very few barrels are under .005" of runout when you dial in the chamber end with a long reach indicator or a grizzly rod. It is hard for a company to drill a 27+" long hole perfectly straight. There are way too many thing that can and will prevent it from going perfectly straight. Several companies are using hones on the bores prior to rifling and it seems to help a bit. Just because the bore isn't perfectly straight doesn't mean it won't shoot good. Most barrels shoot really good even with .020-.030" of run out.

Idaho CTD. I am using your post only because you brought up some good points and not to start an argument or criticize so don't take it as an attack (Please).

I know that Most barrel makers are hesitant to give away there process and it is sometimes hard to get them to talk about it (Some processes are proprietary and they feel that that's there edge over other barrel makers. Deep hole drilling takes skill and the proper tools to be done correctly. some of the better barrel makers can/do make barrels up to 45" that are very straight.

First of all the better quality barrels are first drilled. next they are reamed several times to get the proper straightness. If this straightness is not within there tolerance, they drill it to a larger size and start the reaming process over for the larger bore size. if the barrel blank doesn't make the tolerance the second time then it is scrapped.

Once the barrel bore is straight, it is finally reamed to produce the proper bore size for rifling, then the rifling is done and only then by the better barrel makers. Cheaper barrels cant afford this much care and precision in order to sell at there price, so it is not done. They do all barrels and then grade them based on there straightness. They may have as many as 4 different grades.(You get what you pay for).

I don't think anyone really knows how much out of straightness hurts accuracy, But most know that straight is better. Also we don't have the instruments that the barrel makers have to check straightness or bore diameter and even finish. So all we can do is try to verify the quality with what tools we have. They (The good barrel makers) have lasers that can measure the entire length of the bore for straightness, we don't. but if we are diligent while check a barrel, we can tell if it is one that is within advertised specifications or very close.

I once bought 5 new Sendero barrels and after checking all of them I found barrel straightness to be .001, .003, .007 .014 and .032. I did not use the .032 barrel but was toll that the .014 would be fine. after setting the chamber back (To get consistent and clean chambers) they were all chambered in the caliber (300 RUM) with the same reamer and bedded into the laminate Sendero stocks. after completing all 4 rifles the rifles with the least run out shot the best, and oddly enough progressively worse as the run out got worse. the barrel with .014 straightness had to be replaced with a custom barrel to fall under 1/2 MOA (I am glad that I didn't use the .032 barrel).

Could some of the difference been the rifle just did not like the loads as well. Absolutely. But it was strange that they got progressively worse as the run out numbers got worse.

So I no longer except a barrel that has more than ,001 or .0015 run out. Is this to stringent? Probably. But when I get a barrel that will get below .0001 with my gauges I know I have a good one, and the outcome is in my hands.

Demand the best, and you will get the best. In my opinion, barrel making is an art if done right and consistent quality is the mark of a great barrel maker.

Everyone should visit one or more custom barrel makers and see what goes into making a great barrel and then you will understand why there are poor barrel makers that are only in it for the money.

This has been a very interesting post and as usual, I have learned a lot from it also.

Just more comments.

J E CUSTOM

 

[IdahoCTD]

I tend to recommend and gravitate towards Bartlein because they have been the straightest and the most accurate, on average, for me lately. Inevitably every button rifled company I've ever used has disappointed me eventually except for Schneider. That is with at least a 10 barrel sample. So anymore I almost always choose cut rifled barrels.

How was the barrel .014" out "dailed in"? How did you measure the run out? It would be interesting to set that barrel back and chamber it the way I do it, if it's different then what you did, to see if it shot better. I might buy a cheaper barrel, since they tend to be the most "curved", to test the different ways of dialing and chambering a barrel.

BTW I don't take offense. If there is something I can learn I'm all for it. I chamber the way I do because it makes more sense to me. It takes longer to dial a barrel in but it is worth it to me. If someone proves another method is more accurate I'm all ears.

 

[J E Custom]

BTW I don't take offense. If there is something I can learn I'm all for it. I chamber the way I do because it makes more sense to me. It takes longer to dial a barrel in but it is worth it to me. If someone proves another method is more accurate I'm all ears.

Great !!!! +1

Everyone has thee way of doing things that works best for them and as long as no one takes disagreement personally this is the best sight available. There are some really great minds on this sight (excluding mine) and we can all benefit from them.

The main point I was trying to make was not to except poor quality and the better barrel makers will only get better.

Thanks
J E CUSTOM

 

[Canadian Bushman]

Great !!!! +1

Everyone has thee way of doing things that works best for them and as long as no one takes disagreement personally this is the best sight available. There are some really great minds on this sight (excluding mine) and we can all benefit from them.

The main point I was trying to make was not to except poor quality and the better barrel makers will only get better.

Thanks
J E CUSTOM

Im very curious how straight a barrel can be cut, and how many makers are not straight forward about their tolerances and "grades".