barrel question. Could a ss barrel be too hard to ream????

[oldfamily]

Question is about the 257 stw that I am having built. MY smith has had one reamer break and the other twist trying to ream out the chamber. Both reamers were brand new one broke in half, and the other twisted. My question is could the barrel be too hard to ream. I called the barrel company and they are having the barrel returned to see if they can chamber it. I am in quality controll for a living and this crap has got me thinking of the quality of work that goes into this barrel. I know that this is the last barrel that I will purchase from this company. I have not put the name of the company because I am waiting to see if they make things right. I do know the reamer company asked what barrel that was being reamed and when they heard they acted like they had this problem before. I just wish to get this thing finished so I cam start putting some round down range. Oldfamily

 

[Centre Punch]

Oldfamily,
In my opinion it would be the reamer that is at fault.
Brand new sharp reamers have been known to "dig in" whilst performing a full thickness cut. This can result in chatter in the chamber and sometimes broken reamers.

On the other hand hard spots in the steel can damage tooling. but this is usually more prominent in chrome-moly steels.

Ian.

"I meant to shoot the pike but the duck gt in the way"

 

[dakor]

CM is even harder then SS so I would think it is the reamer not the barrel.

 

[Black Diamond 408]

I had a SS 50cal bbl from a prominent bbl maker and it was almost impossible to ream, it squeeled and squeeked, had all kinds of trouble with it. Sent the reamer back to the company to have it checked, they re-sharpened it and sent it back to me, still the same thing. Then i found the bbl had tight spots in the bore, i returned the bbl, they just lapped it and sent it back. The bbl never did shoot! Hence i never bought another bbl from this company.

 

[Fiftydriver]

Oldfamily,

Could we get a little more information about the reamer. I would assume its a live piloted reamer but want to make sure. If its a solid piloted reamer that has a pilot diameter to large for the bore, you will snap a reamer very easily as the neck of the reamer will be stressed before the body of the reamer engages the barrel fully.

Is your smith cutting a full cut with the finishing reamer or hogging most of the material out with a drill or roughing reamer first?

You should really only remove about 0.050" in diameter with a finishing reamer. Taking a full diameter cut with a finishing reamer is much harder on the reamer. It is very easy to have the reamer bite and either spin in the reamer holder or break.

Not saying your smith is doing anything wrong, it could just be several different things causing this. Like your doing the best thing to do is see what the the barrel maker says and then try to see if it is a reamer issue.

To answer your question though, stainless steel barrels should chamber very easily with a quality reamer and proper chambering techniques. As already mentioned, Chrome Moly steel is much harder then stainless.

Kirby Allen(50)

 

[4ked Horn]

[ QUOTE ]
CM is even harder then SS

[/ QUOTE ]

I'm not sure that this is true all the time. CM and stainless grades used in BBLs should be fully machinable. It isn't untill they are hardened that reaming would becom a problem. I may be incorrect but having been a machinist for a short while that is how I understand it.

This I do know though, SS will sometimes "work harden" in the blink of an eye. I have seen a knurling wheel destroyed because the machinist student made a return pass with the knurling tool while working a piece of SS. I have also seen a machinist or two totally smoke a drill bit because the feed pressure was to low.

With this in mind I think it is possible for the gunsmith to possibly bear responsibility. One attempt to feed the reamer with the lathe running in reverse while distracted with some other business or conversation may have been all it takes to litterally rub a hard spot (the size of the reamers contact area for that process) in the steel. If the gunsmith fails to notice the problem and get below the hard steel the reamer will fail to cut and will snap or twist.

In short, I would not jump on the BBL maker just yet. And I wouldn't ask the reamer company who is at fault either. Who do you think they are going to blame with the gunsmith buying their reamers.

 

[4ked Horn]

[ QUOTE ]
Moly steel is much harder then stainless.

[/ QUOTE ]

Not to hijack the thread Kirb but how is this true? 4140 or similar metals have a certain "toughness" to them but they are not hard per se until they are heat treated. SS is much tougher in it's annealed state and as you are well aware much stringyer (?). The chip is continuous often.

I yield back this thread to the gentleman from Montana.

 

[oldfamily]

[ QUOTE ]
Oldfamily,

Could we get a little more information about the reamer. I would assume its a live piloted reamer but want to make sure. If its a solid piloted reamer that has a pilot diameter to large for the bore, you will snap a reamer very easily as the neck of the reamer will be stressed before the body of the reamer engages the barrel fully.

Is your smith cutting a full cut with the finishing reamer or hogging most of the material out with a drill or roughing reamer first?

Not saying your smith is doing anything wrong, it could just be several different things causing this. Like your doing the best thing to do is see what the the barrel maker says and then try to see if it is a reamer issue.


Kirby Allen(50)

[/ QUOTE ]Live pilot, hogged out, I am sending the reamer and barrel back to see what they make of it. The first reamer broke on a .003 cut, one way to look at it is this is the way my luck runs. thanks all

 

[1doug]

I know what you are talking about. Had similar problems with a 257 stw. My barrel would chattter from 12 rpm all the way to 400 rpm with my reamer light feed to excessivly heavy feed.

The reamer maker told me that the 25 cal pilots are the smallest large diameter pilots he makes, I can send the reamer back an have the pilot shank reground to a smaller diameter and put a thicker bushin on it.

The barrel manufacture took my barrel and reamer and got it to work with out the chattering, i think they removed the bushing and used it as a solid pilot reamer. /ubbthreads/images/graemlins/frown.gif

I already told the barrel manufacture that if it did not meet my accuracy requirements that i would require a full refund. They did not seem to want to talk about refunds at all.

Definatly my last barrel from them

da

 

[Fiftydriver]

4ked Horn,

Maybe the term "harder" is not the correct term that I should have used. How about more brittle??

I would agree that stainless will often machine with continuous foil type chicks as 4130 and 4140 will often chip off into much finer chips.

I will also agree that if you push things to hard with stainless you will get burned, literally!! As you stated with the drill bits and Knurling cutters.

That said, when chambering a rifle, it is much easier to get a fine chamber finish using a tool steel reamer with Stainless barrels then it is with 4130 or 4140 barrels.

Stainless is much gummier when machining then chrome moly. Cutters and reamers need to be watched very carefully when machining stainless and cutting speeds and lubricant levels are much more critical as well.

But when everything is set up correctly, I have always found stainless barrels to be easier to machine then chrome moly. Just my experience dealing with rifle barrels only, not differnet grades of heat treated steel.

I do now that some heat treated stainless steel is nearly impossible to machine no matter what type of cutting tools you use. Can be said for chrome moly as well though.

I have also found that Lilja stainless barrels chamber with less effort that say a Krieger or Broughton. I am sure due to allow used and heat treatment of the blank.

Good Shooting!!

Kirby Allen(50)

 

[srhaggerty]

As a MSE degree student this topic intrigues me. I would think the grade ss makes a difference to. For instance if you are working with a martensitic steel. 410 found in like Krieger barrels are this type of steel. Where Lilja uses 416, a "machinable" steel. I would think this would effect drill wear.

 

[srhaggerty]

Broughton uses 416R. I went and looked up a data sheet on it. It is a hardened version. Kirby I think this answers why you see the difference.

 

[oldfamily]

The one thing that has me wondering is that I had the barrel ordered for 14 weeks and no barrel. Called and asked and they said they did not have any. Then I told them that I had been waiting that long and all of a sudden I have a barrel sent out that evening. I am thinking that the barrel turned into a rush job just to shut me up. Looked at the website for the company and they did not say what steel they were using. Too many what ifs are going through my mind I do know that the chamber end of the blank did have a somewhat strange sound to it, I know the size would make up for some of the difference compared to the muzzle end, just that it was an odd thing that I did notice when checking the barrel when I got it. The contour is a #5 and the one thing that caught my eye with it was that the contour had a bulged look to it after it got to 26 in. I had ordered a 30 in blank the end result was that the turning was not uniform and the barrel does not have the even contour that I would think that it would have. Kind of like a bite out of the metal. Don't know if this is normal, but that was the first thing that I disliked with this barrel. Oldfamily.

 

[LB]

I'm not a gunsmith, (or a lawyer) but have used a lathe and a drill press, before. I don't even know if chamber reamers are available in M42, carbide, HSS or it depends on the barrel steel, but speed and lubrication are critical, as is the pressure to create friction. I dropped a muzzle heavy straight cylinder ss barrel rifle off a bench once. It dented like brass. No problem, just recrowned, good as new. Seems to me that most stainless alloys used for barrels are not hard, they just resist heat better than CM and you pay more money because the tooling doesn't last as long. I think a decent lubricant for stainless is plain water, oils are usually bad.

At this point, you can't say if it is the operator, the tool or the material.

But, the topic question: "could a ss barrel be too hard to ream????" Probably not? Some stainless type nickel steels hardened for knives are a different story, but most ss alloys are relatively soft, some are magnetic.

Good hunting. LB