This can't be good...

[Duster340]

Hey folks,

My brother gave me an old Remington 7400 awhile back. He got it as part of a trade years ago but didn't take it apart, clean (other than a few patches through the bore) or use it other than a trip or two to the range. His recollection is that it shot well...I recall shooting it but couldn't tell you if it function well. Sadly, neither of our memories are getting better these days.

Anyway, I finally got around to taking it apart to clean it. It's clear the PO never disassembled it and it was really dirty. The barrel/rifling, receiver rail, bolt and trigger assembly look great, with very little wear and doesn't seem to gave had a high round count through it. Brother recalls the PO saying he hunted deer with it.

But, as I'm cleaning it I notice what appears to be a crack on the gas port tube. See picture.


Guessing this isn't normal. Can/could the rifle even cycle, fire, eject and feed with that?

Thanks in advance.

 

[Ken T]

It is a crack.Unfortunately that doesn't appear to be a replaceable part.The schematics I looked at show it as an integral part of the barrel.Try to contact Remington about it.They may be able to replace the part at the factory.

 

[.455_Hunter]

I am sure a decent true gunsmith (not an ar-15 assembler and cerakoter) should be able to cut off the cracked tube, drill out the base and install a workable replacement.

 

[edwardware]

That set screw looks suspiciously like it's positioned to retain the gas tube. . . you'll need Kroil and heat though.

 

[skeeterfogger]

That set screw looks suspiciously like it's positioned to retain the gas tube. . . you'll need Kroil and heat though.

For securing ball check.

 

[Duster340]

Thanks for the replies fellas. Think I'll do some single shots to see how it groups. If it's doing minute of deer at 100 yards, I'll look into getting it repaired. Since I've got $0 into it, I'd be willing to get it serviceable. If not, I'll look for a used barrel, or I also recall a place doing 7600 pump conversions. Though not sure they're still around. I'll keep you all posted.

 

[BBBBill]

That tube is most likely silver soldered into the gas block. It should be fairly easy to remove and have a machinist copy it out of 4140/4150 steel.

 

[Duster340]

May try to insert a piece of copper wire then do a little light welding and grinding with a dremel. A bit finer work than the welding I do on my drag car, but guess I've got nothing to lose by trying.

 

[#1buck]

Get Rose Action Sports to look at it. He does a lot of stuff other gunsmiths say can't be done.
https://roseactionsports.com/

 

[Duster340]

Well, I think I may have got it fixed. Inserted a solid piece of copper wire that was an exact fit in the tube. Cleaned up the metal and lightly welded the crack up. Still gotta do a bit of clean up work with the Dremel, then polish it. Won't be able to test it for 2 weeks when I sight in all the deer rifles. If she cycles through a few mags without issue, I'll dial it in and give it a try for one of the many doe tags I have to fill. Fingers crossed!

Thanks for all the replies and suggestions. I'll post up my results.

Be well,

 

[Obturation]

Looks better, i would have borrowed some flex seal from my neighbor and tried that. But it looks like you've got it handled. Wonder why it cracked...

 

[SGW Gunsmith]

For securing ball check.

Yes, that set screw holds the tiny ball to divert the gas from the gas hole that was drilled into the barrels bore using a step-drill. After the bullet passes over that hole, gas is diverted through the hole in the barrel and then that tube with the crack in it and works the action.
I've worked on tons of the Remington 742 and 7400 rifles and I've never seen that tube crack like that. Could be just an anomaly that only happens on rare occassions.

 

[Duster340]

Wonder why it cracked...

Yes, me too! It's weird because the rest of the rifle and action look really good. Don't know anything about the rifle's history. Doesn't appear to have a high round count through it. I'll definitely be keeping an eye on it.

 

[Obturation]

Maybe a stuck case kept the action from cycling and the gas had to get out somewhere?
I'm not familiar with that action so its just speculation.

 

[SGW Gunsmith]

Yes, me too! It's weird because the rest of the rifle and action look really good. Don't know anything about the rifle's history. Doesn't appear to have a high round count through it. I'll definitely be keeping an eye on it.

What I probably would have tried to do, is make a tight fitting sleeve to go over that split tube and then drilled out the long gas tube on the rear end to accept the now slightly larger gas direction tube. Same amount of gas is passing through that tube, only now, it shouldn't split any further.

 

[Duster340]

Great call out. That is a really great idea. Thanks! If this fix doesn't hold up, I will definitely try your fix.

Much appreciated

 

[Duster340]

I've worked on tons of the Remington 742 and 7400 rifles and I've never seen that tube crack like that. Could be just an anomaly that only happens on rare occassions.

Ya, odd for sure. Wondering if it may just be defective piece? In any case, hoping the attempted fix works. It's a neat rifle I'd love to get the old girl back into service as a deer gun.

Be well

 

[Duster340]

Well, took to deer rifles out to check the sights, and finally got the chance to test out the fix on the 7400. Glad to say, I could not be happier! My weld repair did the trick and it ran through the 30 rounds of handloads I brought silky smooth and flawlessly. There was a lot of folks sighting in their deer guns this morning and I only got to play at 50 yards. Which is fine as that's pretty much a long shot in the cedar wetlands I hunt. She really likes 45 gr of 4895 behind a 165 gr SPBT. As I'd heard and expected, the groups opened up a bit when the barrel heated up after a few successive mags but never got out of the minute of deer range. The accuracy definitely benefited from letting the barrel cool down after each mag. She's not a extended rapid fire toy for sure. My old self "Bubba'd" is still my go to deer gun. The 7400 will be in my hands to try and fill one if my 5 antlerless tags this season. Overall I'm happy as pigs in dirt, especially since the gun was a freebie from my brother!

Be well folks

 

[#1buck]

Congrats man!

 

[Duster340]

Congrats man!

Thanks man! It's nice when things work out.....and a little luck doesn't hurt either. LOL.

Be well

 

[FROGO207]

I have one in 308 that is a tack driver myself. They had a rep of the rails in the reciever wearing fast due to poor heat treating so be sure to inspect often and slow down use if yours starts to have this problem.