Cortina & Borden Interview

[WSnyder]

exactly what is his tempering temperature?

Not over 675° as stated in the video. Above 675° he says the Charpy strength goes away.


still we use 416 and we have it hardened to 39 to 41

rockle (Rockwell) uh special heat pre treating process uh because you can heat treat

416 to 39 to 41 rock with a different

bunch of different tempers if that temperature is above 675 de (degrees) fah you get

the same Rock ball reading but you have no Sharpie (Charpy) strength which is impact strength and why is impact strength well

that's the corner of your threads the corner of your raceways the corner of your locking lug seats in the action if

you have no Sharpie strength with high impact loads which you know the the

cartridge going off against the bolt face and the lugs slapping all the time creates impact strength you can end up

with cracks so it's a controlled heat treat for um a

 

[gunsandgunsmithing]

The pin tip dimensions in the old instructions was .062" +- .0005" by .400" long

Here you go:

Thank you. Now that you refresh my memory, I have seen it but I saved it this time. Thanks again!

 

[gunsandgunsmithing]

Not over 675° as stated in the video. Above 675° he says the Charpy strength goes away.


still we use 416 and we have it hardened to 39 to 41

rockle (Rockwell) uh special heat pre treating process uh because you can heat treat

416 to 39 to 41 rock with a different

bunch of different tempers if that temperature is above 675 de (degrees) fah you get

the same Rock ball reading but you have no Sharpie (Charpy) strength which is impact strength and why is impact strength well

that's the corner of your threads the corner of your raceways the corner of your locking lug seats in the action if

you have no Sharpie strength with high impact loads which you know the the

cartridge going off against the bolt face and the lugs slapping all the time creates impact strength you can end up

with cracks so it's a controlled heat treat for um a

Maybe that's a tempering temp. Sounds more like it, 675 for about 4 hrs sound close?

 

[WSnyder]

675 seems low without looking it up. Maybe that's the secret is the long, slow heat. IDK. Still seems low. Maybe that's a tempering temp. Sounds more like it.

Yes, tempering temp. He (Borden) states "not over 675°"

Off of a 416 spec sheet: Tempering of this steel at temperatures of 400 to 580°C (752° to 1076°F) should be avoided due to low impact resistance.

 

[jackieschmidt]

675 seems low without looking it up. Maybe that's the secret is the long, slow heat. IDK. Still seems low. Maybe that's a tempering temp. Sounds more like it.

By industry standards, there is a criticle range of 416 between 750 and 1150 that does degrade ductility.

Borden is well below this. I just missed the 673 degrees F in the interview. With 416, you settle for a RC hardness of just above 40 with good ductility, or have to take it clear down in the mid 30’s with compromised ductility. The weird quirk is when the RC hardness gets into the low 30’s and 20’s, the ductility, as measured by Charpy, shoots up dramatically.

This makes me wonder if all of the other manufacturers of actions who use 416 adhere to this heat treating phenomena.

I really like Jim’s explanations on why ductility is so important in an action. Especially in the critical areas that basically form 90 degree surfaces, such as where bolt lugs meet the bolt body.

There is a lot of great info in this interview.

 

[davidjoe]

Is it really true that a coned bolt tenon is designed to spilt the action and let the barrel go forward in the event of accidental gross overpressure?

 

[Jefferson]

I consider Jim a friend even though we have never met. Definitely one of the guys that really gets actions. Theres not as many of them as you would think. He was the first timed action out there that had good ignition, at least in my opinion. It was a great interview. I do hope he has him on again.

‘I also,consider Jim to be a friend

and we HAVE MET

 

[chris davis]

Wow! So much great info, I was glued to the screen! Thanks Eric and Jim!! Can’t wait til the next video!!

 

[jackieschmidt]

Is it really true that a coned bolt tenon is designed to spilt the action and let the barrel go forward in the event of accidental gross overpressure?

I always thought it was to aid in feeding rounds off the ramp in a single shot.

But if it does indeed do what Jim said, that’s a big plus.

 

[ScottVA]

Is there a picture or drawing of a sectionalized bolt that be seen anywhere?

 

[Alexander-M]

I have enjoyed all of Erik's interview videos, which are very informative. But I agree with the opinions shared above, this interview with Jim Borden is the best. I learned a lot.
Thank you Erik and Jim!
Alex

 

[WSnyder]

Is there a picture or drawing of a sectionalized bolt that be seen anywhere?

This is a picture of PTG’s standard and benchrest bolt head cutaway’s.

 

[WayneShaw]

Is it really true that a coned bolt tenon is designed to spilt the action and let the barrel go forward in the event of accidental gross overpressure?

This is/was one of Jim's actions. Not mine!

 

[gunsandgunsmithing]

This is/was one of Jim's actions. Not mine!

Obviously way over pressure. Jim said in the interview that in such a case, the action is designed to spit the bbl out the front of the action. Looks like it did that part. Add enough powder/pressure and they'll all come apart. Hope no one was hurt bad with that.

 

[dgeesaman]

Finally got through it, not because it was boring, but because it was dense and I didn't want to miss anything. I think episode two will be excellent also.

He runs a tight shop and a tight bolt. After talking with him and getting an explanation about how important action strength is to him (as learned from Mike Walker), I concluded I will only buy custom actions from him. So far I only own one custom but it's a Borden.

As engineers go I greatly respect his closeness to manufacturability. Too many engineers fall into the fool habit of believing that because they put words and numbers on a drawing, that their drawings represent reality. (So too, it takes a better than average machinist to know that what the machine says a part is, is also not necessarily reality!) It takes a good, respectful, dubious look at every little detail of the actual outcome to do something properly well and I trust Jim is doing that.

 

[Evan]

This is/was one of Jim's actions. Not mine!

I value designing for graceful failure much more than strength alone. If folks missed it, they can look up what happened to Scott from Kentucky Ballistics when his Serbu RN-50 blew up from an overpressure round. Pretty much textbook example why a safe design is more thoughtful and intricate than just making it stronger.

All my custom rifles are built by Jim Borden and he has been excellent to work with.

 

[dgeesaman]

I value designing for graceful failure much more than strength alone. If folks missed it, they can look up what happened to Scott from Kentucky Ballistics when his Serbu RN-50 blew up from an overpressure round. Pretty much textbook example why a safe design is more thoughtful and intricate than just making it stronger.

When I visited Jim to pick up my Super Short Six barreled action, he told me the story of how Mike Walker and the Remington engineers developed the 700 action to be stronger and safer than the popular Weatherby actions of the time. They tested both actions to failure and the Weatherby failed at much lower load and much more deadly outcomes than the 700. Mike mentored Jim. It’s clear that Jim has taken those lessons and that philosophy and approach to safety to the highest possible level.

 

[K22]

Thanks for posting. Very interesting interview.

I would love to have him build me a custom varmint rifle but I'm nearing the end of varmint hunting. In the long run, I could have saved a lot of aggravation and money spent messing with factory rifles, trying to get them to shoot, re-barreling, etc. if I instead just had a rifle built by someone like him to my specifications. Something that serious new varmint hunters may want to learn from my mistake.

I went on his website, and he has some interesting information on cleaning rifles. I know, it a controversial subject but I figure this guy is a true expert.

 

[Evan]

Thanks for posting. Very interesting interview.

I would love to have him build me a custom varmint rifle but I'm nearing the end of varmint hunting. In the long run, I could have saved a lot of aggravation and money spent messing with factory rifles, trying to get them to shoot, re-barreling, etc. if I instead just had a rifle built by someone like him to my specifications. Something that serious new varmint hunters may want to learn from my mistake.

I went on his website, and he has some interesting information on cleaning rifles. I know, it a controversial subject but I figure this guy is a true expert.

With the rising cost of components and barrels, the price of a custom receiver is less and less significant by the day.

 

[FNSafari]

M

With the rising cost of components and barrels, the price of a custom receiver is less and less significant by the day.

Right. Generally a SS BR quality barrel is in the $420 range plus $20/30 shipping. Chambering is maybe $200 if you are lucky, so thats $640 min vs a $1500 action. Life of barrel, 30 cal, maybe 3000 shots of competitive accuracy, life of action if taken care of 10s of thousands of rounds. Buy once cry once.