Rough bore in a new barrel ?

[laocmo]

I've noticed in two of my newest purchased handguns, a Kahr CW9 being one, that the rifling is sharp and well cut but in terms of machining marks, very rough. I know lapping the barrel is done to polish the bore and remove machining marks and also to remove any tight spots in the barrel and make it dimensionally uniform end to end. But some like Ackley say, there is, "No need for it, just wears the barrel out!". What's the opinion here. My two guns mentioned above are rougher than a cob, but still very accurate. Is a mirror polished bore just all cosmetic? Thanks.

[Alfonse]

I think photos would help. Other than some rare plating issues, I haven't seen a Kahr barrel that wasn't mirror on the inside.

[laocmo]

I think photos would help. Other than some rare plating issues, I haven't seen a Kahr barrel that wasn't mirror on the inside.

Might be a challenge, but I'll try for a photograph. This is actually the second CW9 I've had that was very rough in the bore. I had a very early model and sent the barrel back for their inspection. They replaced it.

[muggsy]

If we were talking bench rest shooting with high power rifles and your looking for MOA or better accuracy the bore is very important. In a down and dirty concealed carry pistol where you're looking for minute of pie plate accuracy at 21 feet, not so much.

[skiflydive]

Gun barrels are broached, not machined per se. There are examples on YouTube. It's hard to imagine that broaching would leave a rough surface unless chips are allowed to build up in the teeth of the broach. Broaching is usually done with a heavy flow of oil as a coolant/lubricant which would tend to flush the chips away. I don't have an answer to the question but like I said it's hard to imagine. Broaching will not leave "Tight spots." My guess it would be, as Alfonse said, a plating issue.

[CJB]

Almost no commercial barrels are broached (cut) any more. Too time consuming. Button or hammer forging is the way today. Broaching DOES leave tool marks. The most of those three methods in fact.

Kahr barrels are hammer forged. We see plating roughness on occasion as they are plated inside and out. That shoots smooth, no need to lap. A few cratered barrels too but very few ....maybe two examples....in five years here.

[skiflydive]

Almost no commercial barrels are broached (cut) any more. Too time consuming. Button or hammer forging is the way today. Broaching DOES leave tool marks. The most of those three methods in fact.

Kahr barrels are hammer forged. We see plating roughness on occasion as they are plated inside and out. That shoots smooth, no need to lap. A few cratered barrels too but very few ....maybe two examples....in five years here.

Hmmm. Interesting. I've never seen an operation that would finish form the ID of a part by forging. I'll have to research that.

[gb6491]

Hmmm. Interesting. I've never seen an operation that would finish form the ID of a part by forging. I'll have to research that.

Hammer forging barrels:

Regards,
Greg

[AZ Jeff]

Kahr barrels are hammer forged. We see plating roughness on occasion as they are plated inside and out.

Are you sure ALL of the Kahr barrels are hammer forged? I don't doubt the premium polygonal are made that way, but the "value" series could quite likely be button rifled....

[CJB]

Nah. Just sub on mandrel for the other. Premium is a marketing persuasion to boost perceived value and allow greater ROI.