Defective barrel

[Scota4570]

My Manton-esque project got started today. 

I made my hooked breech plug blank .  I screwed it to may barrel.  WT???  The bore at the breech is 0.050" off center.  With 5/8'x18 threads in a 50 cal barrel that leaves no internal shoulder what so ever.  I do not consider this to be acceptable. 

I bought it from an internet retailer.  The have none in stock today. 

Should I complain to the manufacturer and beg for a replacement? 

Push it down deep and slather the treads with goop? 

Throw it away and move on? 

[D. Taylor Sapergia]

Drill and tap the barrel for a 3/4" x 16 plug, and carry on.

[Scota4570]

A 3/4" plug will leave only 1/16" between the major thread diameter and the barrel flat.  Is that sufficient? 

BTW, it was Green Mountain. They were unhelpful, bordering on hostile,  and passed the buck to the retailer.  The retailer can not replace it, and did not make it.  I am having trouble finding the receipt anyway.  [edited to meet ALR rules]

Oh forgot the pictures.

The useless plug cost me a couple of hours so far. 

[Bsharp]

Remember to mark the run-out and index it up or down.

[RichG]

if the barrel isn't inlet, cut off threaded portion and re-drill/tap and align the offset top or bottom.

[Scota4570]

GM put their stamp on the bottom already.  They had to measure the runout to know what flat to put their mark on .  So, they had to have known it was defective when made and shipped it anyway. 

GM has turned their back on traditional shooters.  They no longer offer a good selection of ML barrels.  They stopped all the interesting cartridge gun barrels.  I used to think they made good barrels. Apparently the QC was lacking.  Given they are catering to the "modern" rifle crowd, I predict a bleak future for them.   [edited to meet ALR rules]

Anyway...  Does a 3/4" plug in a 7/8" AF barrel have sufficient meat between the major thread diameter and the barrel flats.  It has about 0.0625" thickness remaining.   

[rich pierce]

The stamp is no big deal unless you want to keep it. File it off. I am confused about the internal shoulder though unless they turned for breeching based off the planed exterior.

[Scota4570]

That is exactly what they did.  The must have bored the threads in a lathe.  The threads are perfectly centered as measured from the barrel flats.  Refer to my picture. 

[Robby]

GM put their stamp on the bottom already.  They had to measure the runout to know what flat to put their mark on .  So, they had to have known it was defective when made and shipped it anyway. 

GM has turned their back on traditional shooters.  They no longer offer a good selection of ML barrels.  They stopped all the interesting cartridge gun barrels.  I used to think they made good barrels. Apparently the QC was lacking.  Given they are catering to the "modern" rifle crowd, I predict a bleak future for them.

Anyway...  Does a 3/4" plug in a 7/8" AF barrel have sufficient meat between the major thread diameter and the barrel flats.  It has about 0.0625" thickness remaining.

If they drop 95% of their business [edited], we all lose, no matter what you shoot.
Robby

[FlintFan]

That stinks.  Fortunately you have a lathe, and it looks like you are very proficient at using it.  Make a plug to whatever size you want.  .650-18, .675-18, etc.

Obviously you would have to use a internal threading bar for the female threads since no tap will be available, but I don't know what other options you would have right now.  It's a bear to chase female threads as well, so it would probably be much easier to cut the breech off if you wanted to try that.

I would agree that a 3/4" thread would be a bit big.

You might be able to find some taps out there for a 11/16" thread, if you wanted to stick with that route.

[Bsharp]

if the barrel isn't inlet, cut off threaded portion and re-drill/tap and align the offset top or bottom.

Yup, cut it off, center it up on the bore and re-drill and tap.
You appear to be making your own plug, so the centered thread will not matter.

[FALout]

I’ll give ya $20 for that fancy tomato stake, might even be willing to pay shipping.

Just kidding

Seen lots of barrels like that years ago, either you shorten it or use as is, not like it’s unsafe tho.

Some years ago, I bought a barrel here that I didn’t notice any trouble till I was ready to put into a stock, it was made by someone I won’t mention.  I needed a tapered barrel and thought this swamped barrel would be perfect to chop shorter.  Well when I did cut it down, I found the drilling had run out so close to the edge it would have blown if used, got mad and kept cutting back till all I had left was enough for a pistol barrel.  Expensive lesson for me.
I’ve never used a GM barrel, so won’t say anything bad about them, but I remember learning how to cut/thread barrels without a lathe, then later how to use a lathe, that’s how it was when you couldn’t buy high end barrels like you can today.  It’s why lots of builders use Rice barrels, they know what they are getting.  Sorry about the headache this is giving you, buts part of building sometimes.
Bob

[Scota4570]

I'll figure something out. 

Boring internal threads to a shoulder is not easy task.  I may pay up for an 11/16 tap and die.  The new dies have a tape on both ends so threading up to a shoulder is impossible. 

Since my rectangular stock is 1" x 1 1/2"  and the barrel is 1/8 AF  I don't have much wiggle room to make the breech plug fit the outside.   

It is frustrating because I had a plan and now it is void. 

GM?   Mistakes happen.  When I make a mistake that impacts somebody, fixing  the mistake is my highest priority.   I do not see that much any more.  Most of the time the customer is a faceless and disposable cash dispenser at the other end of a computer wire.  I am old fashioned in my values.  It rubs me the wrong way to be treated like that.   

I hope the other barrel makers get caught up soon.  I have lots of project ideas. 

[Dennis Glazener]

I made some edits regarding subjects that are against our rules i.e. gun control/politics but want to leave the thread for others to know of other issues but I am going to lock the topic.
Dennis