M14 Forum

Rojkoh · February 6th, 2012, 04:11 AM

Quote:

Originally Posted by Bolt2bounce

Thank you guys for your help and input.. Jim thanks for the offer of help.. but you are too far away to help me.. I haven't built a M14 (clone) in a long time about 6-7 years, and my brain doesn't work as well as it use to..(not that it ever did work that well.) The other guns I've built. I used surplus military barrels so they were already barreled..in the past, so of course they would go on easier.. except two guns which were not SIA chrome lined barrels and were short chambered.. so I had to use a pull through reamer.. on those guns to headspace them.. This one was the first time I've used a Forged receiver..and chrome lined aftermarket barrel.. Thank you M-14 (Jywolf) parts for that 18.5 fluted barrel it is beautiful...and the price was VERY reasonable.( with a discount) The threads were just a touch tight, maybe park on the receiver threads.. barrel would go on by hand, it just required a little bit of effort.. so the threads on both receiver and barrel were just fine..I got it barreled, but If I had to guess I'd say the barrel shank needed a few thousands taken off, I didn't have access to a lathe although I do own one..so I just got a cheater bar and disrupted some metal on the barrel shank (not recommended but I did it anyway.. it's mine and I took the risk.. it may be a bit over torked..but I think it will not be an issue..as standard tork is over 100 pounds..it may be 150pounds..let me say hats off to both receiver and barrel manufacture.. head spaced was dam near perfect using a SA USGI bolt.. I'm very pleased at the result.. a pic for ya.. B2B

Just so everyone is aware, DoD fired off a memory on USGI bolts and to take great pains to keep track of the condition of them. From over use and lousey maintenance, they're starting to crack. No, this doesn't mean Surplus parts are abused, but it's a good idea to keep an eye on your weapon and it's condition.

Is your receiver one of the 762 drop forged or LRB? I am interested in building a rifle off a drop forged receiver since M14s were all drop forged instead of investment cast. I loved Elmer Ballance's castings, but I've seen some troubled Genesco's M1As, They do make a fine .45, I carried one of their commanders for some years.

YardDogOne · February 6th, 2012, 07:10 AM

Did somebody say something?

jbrooks · February 6th, 2012, 08:35 AM

Quote:

Originally Posted by Rojkoh

Just so everyone is aware, DoD fired off a memory on USGI bolts and to take great pains to keep track of the condition of them. From over use and lousey maintenance, they're starting to crack. No, this doesn't mean Surplus parts are abused, but it's a good idea to keep an eye on your weapon and it's condition.

Is your receiver one of the 762 drop forged or LRB? I am interested in building a rifle off a drop forged receiver since M14s were all drop forged instead of investment cast. I loved Elmer Ballance's castings, but I've seen some troubled Genesco's M1As, They do make a fine .45, I carried one of their commanders for some years.

Rojkoh, I am aware of only a single batch of USGI bolts that were problematic in WWII and they were all recalled nad destroyed. I'm not aware of any bolts starting to crack from overuse and "lousey" maintenance. Do you have a copy of the "memory"?

I believe the OP stated it is a 7.62 receiver in the title...and I don't think they are "drop forged".

JWB

Jgun · February 6th, 2012, 08:38 AM

I'm presently waiting for a chamber reamer to proceed with my build. I just want to confirm what I'm getting from this thread. I have an M25 receiver and Krieger 22" stainless heavy barrel. Mine hand times to betwwen 7:00 and 7:30. The left side of the barrels left bullet feed ramp is just below the the lip that protrudes from the bottom of the receivers left bolt lug track at the front. I figure that works out to between 30 and 45 degrees needed to time it to vertical. I'm assuming that would call for me to face some materiel from the barrel shoulder. Can anyone give me an idea how much I would need to remove? I see that on page 94 of Kuleck and McKee's book they show different pictures of the barrel timed in different locations. they say that at 7:30 I'm looking at about .004 linear movment to index to 6:00. but I don't see anything about removing material to get the barrel to hand time to 6:30-7:00. Would you experienced builders suggest that I remove .002" from my barrel shoulder?

jbrooks · February 6th, 2012, 09:25 AM

The thread picth is 10 threads per inch, so it has 1/10" linear travel per rotation of 360 degrees. So for every degree of rotation it means 0.00028" of travel. (0.10/360)

So 15 degrees of rotation = 0.0042" (half-hour on the clock)

30 degrees = 0.0083" (1 hour on the clock)

So to go from 7:30 to 6:00 (1 1/2 hour) you will travel 0.0125"

Not sure why the book says 0.004"... unless they meant to remove 15 degrees worth of shoulder and then tighten the remaining 30 degrees to get to 6:00.

JWB

Here's the thread spec from Drwg. F7790189...

Jgun · February 6th, 2012, 09:26 AM

Last time I checked the site, 7.62 lists both cast and "forged" receivers for sale. Don't know if they're drop forged like LRB's or just machined from forged steel like SEI's.

Jgun · February 6th, 2012, 12:12 PM

Thanks for the diagram. I didn't know that the barrel thread was 10 pitch. Now if I could take this a step further. I understand that based on the math my barrel shoulder would need .0125" removed to hand time to 6:00. Can you guys tell me where you like them to hand time to, so that a barrel with a flat, non tapered shoulder, tightens on to the receiver ,with the correct amount of torque, (80-100 fp) when timed to 6:00?

82nd ABN · February 6th, 2012, 12:21 PM

I see something in the post above that has me a bit concerned. You wan't the barrel to hand index at about 7-730 not 6 like you mentioned at the end of the first sentence. Maybe it was a typo or something.

Jgun · February 6th, 2012, 03:25 PM

I probably (as usual) didn't making myself clear. I was just stateing that I understood that, based on a 10 pitch thread where each full 360 degree revolution of the barrel should mathamatically equal .100" linear travel, that from 7:30 to 6:00 should equate to 45 degrees and .0125" linear travel. I'm just trying to get a consensus of where most of you like your barrels to hand time in order that they have the proper torque (but not too much) when they are timed so that the front sight is horizontal, and based on the way the barrel is mfgd, that should put the gas port at 6:00 on the bottom, along with putting the center between the two feed ramps at 6:00 as well. Are you saying that if my barrel hand times to 7:30, it should be at the proper torque (80-100 FP) when tightened another 45 degrees? It just seems as though it would take way more than 100FP of pressure to get the barrel to rotate another 45 degrees after the barrel shoulder is hand tight against the receiver ring.

jbrooks · February 6th, 2012, 04:00 PM

You are correct. Squeezing .0125" of the shoulder just by torqueing the barrel would certainly require more than 100 FPf of torque, I would imagine. But somebody more knowlegeable will be able to answer.

I have a pull-off Wilson that I removed from an SAI receiver (it was installed at the factory). The shoulder is "upset" , having been deforemed by the torque when the barrel was installed. It is 0.01" larger at the shoulder than just behind the shoulder, but I have no way of telling how it hand-tightened originally. Neither the USGI replacement barrel, nor my Poly receiver/barrel show a similar upset.

JWB

BlunderDog · March 8th, 2012, 05:06 PM

Quote:

Originally Posted by Jgun

Can you guys tell me where you like them to hand time to, so that a barrel with a flat, non tapered shoulder, tightens on to the receiver ,with the correct amount of torque, (80-100 fp) when timed to 6:00?

Quote:

Originally Posted by Ted Brown

It should be about15 degrees or slightly over. 30 degrees or more will require excessive torque.

Quote:

Originally Posted by 82nd ABN

Or you can do it the dipsaw way and get a piece of sandpaper out which o dont recommend.

It is easy to crack on someone with impunity, when they are not present to defend themselves. Shame on you. I figure that this makes Gus Fisher a no account smith too, since he is just as adept with a file as Ripsaw is. Go to Gus's forum and read the gunsmith thread again. I have personally met Rip and seen his smitty abilities firsthand. I have shot some of his vast collection of M14's that he built, so I would take his recommendations over yours any day. He told me that he left here because of people like you and their attitudes on such matters. There is more than one proper way to skin a cat, according to Gus.

Kudos to you Blademaker !
Your machine shop skills and equipement are legendary in the field of knives. I know you know a straight cut when you see it. Your mill and lathe set-ups in your shop will get the job done, even on M14's. Hope to meet you soon someday from speaking with Rip. He speaks highly of you as well.

To Jgun, your rough index question is answered in Ted's quoted post above, good luck with your LRB build .