Quick Change barrel parts

After many trials and tribulations over the last year, my Machinist/Coyote hunting friend and I were able to finally finish the quick change barrel kit for our Impulse predator rifles.
I've been using my rifle for all of the R/D + load testing.
I have close to or over a thousand rounds total of 243/ 260 through the rifle and it's holding up great so far and it's still shooting sub MOA with the 6mm 68 grain berger flat base target and 139 grain match burners in the 260.
I black/blued the parts for weather resistance, but they didn't come out as dark as I wanted, but the finish is very durable.
The fourth pic is of the new extension after almost 200 rounds fired without cleaning and multiple barrel swaps.
I also designed a barrel nut with flats on it, so it can be manipulated with a big adjustable and that makes it easier to headspace using the barrel vise.
I set up two barrels (Factory, fluted.243/.260 Rem) with the kit and the carbon fiber with the factory extension, but with a new barrel nut and recoil lug.
It takes under two leisurely minutes to change barrels using one 1/8" Allen T handle.
I didn't torque anything, just tightened till it felt tight and haven't had any issues with it holding zero.
I'm done testing and have set my rifle up with the carbon fiber barrel in prep for the upcoming NY predator season.
Enjoy,
SJC
[IMG]https://i.postimg.cc/Th6G6frT/IMG-1520.jpg[/IMG][IMG]https://i.postimg.cc/Lh3qdyg0/IMG-1512.jpg[/IMG][IMG]https://i.postimg.cc/nM28f7F1/IMG-1506.jpg[/IMG][IMG]https://i.postimg.cc/hX5cWm0Y/IMG-1529.jpg[/IMG][IMG]https://i.postimg.cc/xXxTfh9t/IMG-1522.jpg[/IMG]

That is very encouraging for us wannabe Impulse shooters!

Keep us posted!

random thought.. can the adapter be made to accept large and small shank barrels?

Quote:

---

Originally Posted by Blue Avenger

random thought.. can the adapter be made to accept large and small shank barrels?

---

The extensions we made will only fit small shank barrels.
Not much difference in small and large shank barrels, but the less meat on the extension, the less I would want to chamber a rifle in a larger magnum caliber, especially when the receiver is made out of aluminum.
We would need to see the 300WSM barrel extension to see the differences.

makes perfect sense, I have not seen one yet.

Quote:

---

Originally Posted by Blue Avenger

makes perfect sense, I have not seen one yet.

---

I know the barrel parts we made are made with metal certified to handle almost four times the pressures of any cartridge that has a .473 or .532"" rim diameter.
The thinner barrel tenon and/or barrel extension needed to fit the .555 case diameter of the Wsm would need to be really tough to handle the high pressure and I think that's why we haven't seen a rifle chambered in Wsm yet.
Maybe their planning on making a larger action for the WSM type of cartridges.

Quote:

---

Originally Posted by shoots100

I know the barrel parts we made are made with metal certified to handle almost four times the pressures of any cartridge that has a .473 or .532"" rim diameter.
The thinner barrel tenon and/or barrel extension needed to fit the .555 case diameter of the Wsm would need to be really tough to handle the high pressure and I think that's why we haven't seen a rifle chambered in Wsm yet.
Maybe their planning on making a larger action for the WSM type of cartridges.

---

Made out of something stronger than the 110 action? The barrel doesn't hold the cartridge pressure like it does on the 110 with the large shank?

BTW. Nice work on the components. Are you going to Post or PM drawings? :)

Quote:

---

Originally Posted by Robinhood

Made out of something stronger than the 110 action? The barrel doesn't hold the cartridge pressure like it does on the 110 with the large shank?

BTW. Nice work on the components. Are you going to Post or PM drawings? :)

---

The 110 receiver is made out of steel, the Impulse receiver is made out of thin Aluminum that's surrounding the steel barrel extension and barrel.
I wouldn't want to thin those parts to accommodate the large diameter WSM case.
Drawings won't help anyone that doesn't have the machinery and very costly carbide tooling needed to machine heat treated metal.
Not to mention the custom line up jigs needed to make the extension + lug and the expertise to get those jigs to mesh with the machines to create parts with less then 5 thousandths tolerances.
This wasn't plug and play and if I would've known the costly issues we were going to have to overcome before we started, I would've just bought a couple of rifles to get the parts and called it a day.
The factory barrel extension was hand fit to the lug, as the anodizing was removed in some places and it was like that before I shot the hell out of it.
Our parts are made to much closer tolerances and don't need to be hand fit.
That cost me a pretty penny and a lot of sleepless nights to accomplish.

There may be people on here that have the tooling for anything below 45 Rockwell C. If you used 4140 or anything with a commercial HT it is probably less than 35 RC. Holding .001" may not be an issue either.....I was thinking large shank for the WSM. Sorry to hear you got stressed out. Single pointing the threads is probably the hardest part. I always make a gauge when threading bores. Go on one end and no go on the other. I have been known to do an undersized one also to tattle tale when I am getting close. Not as hard but 416 may be a better option for what it is.Regardless, I really enjoyed seen the finished products.

We used cold rolled steel for all of the testing, then destroyed a lot of semi expensive tooling practicing on heat treated steel till we got the process and coolant application down.
Then we destroyed all of the cold rolled steel parts, as we didn't want any of them to be mistaken for heat treated parts.
Once we made a set that passed inspection and testing at the range, We bought the real expensive tooling and made better jigs to make the finished parts you see here.
All of the final dimensions are in the machinists computer.


[IMG]https://i.postimg.cc/dDLLK7C1/Impulse-parts.jpg[/IMG]

Did you PMI the OEM parts to ID the material and did you test OEM for hardness? The millwork on the recoil lug looks cnc. Did the machinist reserve the right to manufacture and sell parts? Again Really nice to see someone take this on.

Quote:

---

Originally Posted by Robinhood

Did you PMI the OEM parts to ID the material and did you test OEM for hardness? The millwork on the recoil lug looks cnc. Did the machinist reserve the right to manufacture and sell parts? Again Really nice to see someone take this on.

---

HAAS750SS mill and CNC lathe did all the work.
Didn't check anything on the factory parts but the dimensions and since they were sloppy, we tightened them up a bit.
We used certified hardened material, so I'm not worried about the strength, but I did put a few flak jackets over the rifle and used a string for the first couple of high pressure rounds I fired during range testing.
My friend owns a small but well equipped machine shop and I was there to help design, test and make the jigs needed, plus pay for all of the tooling + material.
All this occurred when we both had the spare time to work on the project and when the machines weren't being used between jobs, which was usually very late at night.
That's why it took a long time to complete and why I won't ask my friend for anything.
I'll talk to my friend about coming up with a price for the parts while we're coyote hunting this weekend.

Very nice.

Had two sets professionally black oxide treated to see if it was worth doing and it was.

https://i.postimg.cc/3WwM0PQJ/Impulse-Part-1.jpg
https://i.postimg.cc/5XdkgrTz/Impulse-Part-2.jpg

I'd be willing to entertain one or two of these when you figure them out. Been thinking about swapping my 308 to a 6RemAI. Would love to discuss further

Quote:

---

Originally Posted by RooksR6

I'd be willing to entertain one or two of these when you figure them out. Been thinking about swapping my 308 to a 6RemAI. Would love to discuss further

---

All figured out and tested.
Never shot a 6RemAI, but it has a .473 rim dia, so it should be good to go with the .308 bolt head.
What model Impulse do you have ?
You might be restricted to single shot use in the Predator model if the OAL is to long to fit in the magazine.
SJC

shoots100,
You've done a great job with this mission and also with the pictures and descriptions of the challenges and solutions.

My compliments to you for this effort, that is helping/educating all of this community.

Has Savage made Impulse barrel extensions available as a separate part yet?

Quote:

---

Originally Posted by E6Chevron

shoots100,

Has Savage made Impulse barrel extensions available as a separate part yet?

---

Not that I know of.
The extension part is taken care of, what I would like is a .378" rim diameter bolt head, so I can chamber my Predator in my favorite 20 cal cartridge, the 20 practical.
Being I can't get the smaller bolt head, I'm currently in the process of building a 20-250 chambered Predator to work around that issue.

SJC

Quote:

---

Originally Posted by Blue Avenger

random thought.. can the adapter be made to accept large and small shank barrels?

---

The barrel extension that fits in the Predator model is the same dimensions as the Elite Impulse chambered in 308, except it's threaded for large shank barrels.
The Elite rifles use large shank barrels.
The barrel extension wall thickness of the Elite 308 is really thin, but if Savage is selling the rifles, they must've tested them before shipping them out the door.
I would hope savage is going to make a larger sized action to fit a larger sized barrel extension for the 338 lapua chambered Impulse rifles.

SJC