Gunsmithing My first rifle build

T

Twisted300Win MAG

Sergeant
Full Member
Minuteman
Apr 16, 2012
439
16
39
Michigan
#1
Over he last year and a half I'v been working towards building my own rifles. slowly accumulating the tools and parts needed to put together my first one. Once i had all the parts I took Up an offer from a local rifle builder do do it in his shop with him standing over my shoulder to answer any questions and to make sure I didn't screw up.
The build list.
Stiller Predator SA
Seekins aics dbm
McMillan a5 sniper fill
Rock Creak 6.5mm M40 5r finished 24.25"
Jewell trigger
Vortex Viper PST 6-24x50 Mill\Mill
Chambered In 260AI Match

Parts
Dialed in to 0.00015

Fitting the recoil lug

Threaded

Action fits smoothly with no slop

Reinletting the stock for my dbm because Mcmillan cut it for the wrong one.

Bedding

Bedding 2

Bedding 3
 
#2

Clean up1

Clean up 2

Final assembly

Results during fire forming.
Forming load
140 A Max 0.010" jump
Lapua brass
CCI large rifle primer
47gr H4831sc

I'm pretty pleased with the results so far. If it will do that with forming loads then I cant wait to see what it will do when I work up a load for it. Thanks to the people who have helped me they know who they are.
 
#6
Yes it is an awesome feeling. Cant think of anything i'd change. I have another Rock Creek in 6mm on hand and a 6XC reamer in transit to make it a switch barrel. I might add a APA little bastard in the future but that's it.
 
#7
You did a fine job! I do have one question though. If you were going to use a thread relief cut, why not do it at the barrel shoulder and thread to it there reather than having the shelf for the recoil lig to sit on AND a thread relief?
 
#9
The relief at the tenon shoulder junction is to remove the radius from the tool insert so the recoil lug sits flush against the shoulder. The relief cut between the threads and tenon for the lug is so the threading tool could have a place to empty into open space. The thread major diameter is 0.002" smaller then the lug shelf to creat a slight flat on the top of the threads so they fit to the thread pitch diameter not the peaks of the threads. I'm not a machinist but that's the way I learned.
 
#10
I understand what things are, i was womdering why your mentor suggested you do it that way rather than thread to the shoulder like many do or make your thread relief cut AT the shoulder like others do. I have never seen a barrel tenon set up like yours and was wondering if there was a specific reason i wasnt aware of. Looks like it worked fine so rock on. Dont be surprised if formed brass shoots no better than your fireformimg loads though. I shoot a lot of odball stuff that requires forming and often find that to be true.
 
#12
I basically learned to run a lathe when I bought mine last year. Had a few machinist friends to ask questions, and read a lot. Bought a bare M700 action and started practicing cutting and threading to fit that. I chopped down the barrel on my .308 and recrowed it.
 
#13
selfbowhunter said:
I understand what things are, i was womdering why your mentor suggested you do it that way rather than thread to the shoulder like many do or make your thread relief cut AT the shoulder like others do. I have never seen a barrel tenon set up like yours and was wondering if there was a specific reason i wasnt aware of. Looks like it worked fine so rock on. Dont be surprised if formed brass shoots no better than your fireformimg loads though. I shoot a lot of odball stuff that requires forming and often find that to be true.
Click to expand...

He has a clean area for the lug to seat on this way.
 
#14
I think if you are going to have a thread relief then you did it perfect. I would want my recoil lug to have a nice slip fit with no slop and the only barrels I have seen where the recoil lug rides on the threads are the ones that use barrel nuts like Savage and personally when I rebarrel a Savage I throw the barrel nut away and do it just like you did this one.

Great Job!

Gary
 
#15
Dittos on fire forming loads shooting as well as ammo put up in fully formed cases. There may be a slight increase in accuracy when you work up loads in formed cases, but it's usually not much - not that this is a bad thing, as your fire form group is pretty danged nice already. I've got a couple of 260 Imp 30* rifles, and fire form with some surplus ball powder & both Lapua & Sierra 123s - my 100yd groups while zeroing scopes have been as small as .163" c-t-c, and they'll hold well under 1 MOA at 600yds. I do the majority of forming while shooting matches with FF ammo.
 
#16
chipsfan said:
He has a clean area for the lug to seat on this way.
Click to expand...

what does that mean? the lug "seats" against the barrel shoulder. if you mean "sit", the lug doesn't care wether it sits on threads or not. the only thing I see is that he gave up a thread or two of engagement doing it that way. why not thread it to the shoulder and you would still have .150 or so for a place for the lug to "seat" and still not give away the thread engagement. either way, I was wondering if there was a purpose to doing it that way. it shoots fine and that's all that really matters. just didn't want to miss a new technique if its better. I just cut the tenon to 1.0625 and thread to a relief at the barrel shoulder. I have never had any kind of an issue doing it this way regardless wether the lug has a tight slip fit or .005 clearance!
 
#17
selfbowhunter said:
what does that mean? the lug "seats" against the barrel shoulder. if you mean "sit", the lug doesn't care wether it sits on threads or not. the only thing I see is that he gave up a thread or two of engagement doing it that way. why not thread it to the shoulder and you would still have .150 or so for a place for the lug to "seat" and still not give away the thread engagement. either way, I was wondering if there was a purpose to doing it that way. it shoots fine and that's all that really matters. just didn't want to miss a new technique if its better. I just cut the tenon to 1.0625 and thread to a relief at the barrel shoulder. I have never had any kind of an issue doing it this way regardless wether the lug has a tight slip fit or .005 clearance!
Click to expand...
I really didn't give up much thread engagement. The majority of the relief is under the lug. While I've practiced threading with no relief. This was done on someone else's machine, and that's how it was requested it be done.( less risk of crashing) I don't see a problem with it, so I went with it. However I am open to learning different ways. It shoots good and hasn't blown up in my face yet so I'm happy.
 
#18
Looks great!!!!!

SBH,

The relief by the shoulder is to remove or "lower" the radius left by the turning tool. I do the same thing, though mine are a bit smaller. As for the big thread relief, Ive had a few through my shop that were done that way. They worked fine. I generally thread one turn or so under the lug.
 
#20
Twisted300Win MAG said:
I really didn't give up much thread engagement. The majority of the relief is under the lug. While I've practiced threading with no relief. This was done on someone else's machine, and that's how it was requested it be done.( less risk of crashing) I don't see a problem with it, so I went with it. However I am open to learning different ways. It shoots good and hasn't blown up in my face yet so I'm happy.
Click to expand...

Plenty to be happy for! Great shooting rifle. I can certainly appreciate him not wanting to crash the machine. Been there and done that!
 
#22
#24
Gene is correct. It works well. I have one of my own mounted directly to a backing plate so i can get it as close to the spindle bearings as possible. I also have a spider on the outboard side of my headstock and a spider that i made out of a threaded back plate so i can work on barrels though the headstock. However i can only work on a 23' barrel though the headstock. I plan on using the fixture for shorter barrels and truing actions. Cant beat the price. and Bob is a hell of a nice guy too boot.
 
#26
chipsfan said:
He has a clean area for the lug to seat on this way.
Click to expand...

The lug seats on the faces, not the tenon. What happens if the hole in the lug isn't dead nuts perpendicular to the lug faces and you have a very close slip fit? Really, you shouldn't need a thread relief if you are using a thick lug. Even if you thread half way into the lug thickness, it still has plenty of room to center and you have plenty of time to safely disengage the half nut and retract your tool. I've been using a slight thread relief that I put in using the threading tool when I am done threading on certain one-piece receivers where their counterbore is less than a pitch depth. I can thread up to a shoulder but as I am pulling the tool out, that last thread is not full depth.

But good job Twisted on your first!
 
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