- Location
- Steel Town
Can a rifle chamber insert be made for 308 to 7.62x39? The dimensions seem possible.
Rifle Chamber Insert Q
- Thread starter The Kurgan
- Start date
- Location
- Steel Town
Fair enough, I suspect you are right.
- Location
- Western Manitoba
I am sure that I have seen pictures of a section of a rifle chamber - with an insert - the insert had been soldered in, I think? - gases from the higher intensity center fire had got into the solder, was working away at the joint between the insert and the original chamber. I do have such a chamber insert for shotguns though - actually a pair that go into 20 gauge chambers for using 28 gauge shells - do not seem to have any issues, but do not recall ever firing even 10 rounds in a row without removing the inserts??
- Location
- Western Manitoba
I found what I thought that I had seen - was on dutchman's site - from a conversion done to Chilean 1895 converting from 7x57 to 308 Win by complete chamber replacement that was soldered in, then rebored, re-rifled, etc.
The description that went with this picture reads, "The gap in front of the chamber is thought to be caused from gas cutting of the soft solder joint."
The description that went with this picture reads, "The gap in front of the chamber is thought to be caused from gas cutting of the soft solder joint."
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Blastattack
CGN Ultra frequent flyer
- Location
- Winnipeg MB
The gap is very clearly caused by the insert not properly fitting due to it being a different shape. It is most definitely not caused by gas cutting.
The mismatch of the shape likely gave the opportunity to gas cut the solder, but I would bet my last nickel, that the solder started out as a complete fill.
Meh. In any case, it just highlights that the details matter, if you want it to keep working...
Wonder what was going through the gunplumber's mind when he sees a ring around the barrel ahead of the chamber, and a wire disappears into it...LOL!
IIRC the Americans tried an insert in 30-06 chambers to use .308 Win, and had issues with the insert staying secure too.
Consider the Swiss rifles converted to .30-30 and .308 with sleeved chambers. Anyone ever heard of one failing? Anyone ever sectioned one?
Drop in cartridge/chamber adapters seem to work when lower pressure cartridges are involved. It is when higher pressure rounds are concerned that things could get interesting.
Drop in cartridge/chamber adapters seem to work when lower pressure cartridges are involved. It is when higher pressure rounds are concerned that things could get interesting.
Unless there's something wrong with the rifle or it's a particularly weak design, which I seriously doubt if it's chambered for 308Win, the few thou difference in bullet diameter will not be of any concern, safety wise. It may not be conducive to good accuracy though.
I've owned rifles with such chambers and fired a lot of rounds through them. Neither gave stellar accuracy but good enough for Deer hunting, with iron sights out to 200+ yards. I had heard of gas cutting, but it certainly wasn't noticeable in either of my rifles.
I have one of those Chilean conversions in my safe right now. It was converted to a sporter when I got it and it shoots very well, with ammo it likes. Your post got me curious, so I had to pull it out and have a look with the endoscope. The junction between the insert and the barrel is almost invisible, more like a shadow line.
To be honest, I didn't even realize the chamber was in an insert, until Potashminer posted. My concern with the insert would be concentricity to the axis of the bore.
Drilling and rifling the barrel/insert after it was soldered in was a good idea.
The Swiss rifles weren't done that way.
I suspect that you're asking about a "removable insert"???? for your 308 Win chamber???
IMHO, it isn't doable.
The reason I say this has nothing to do with the bullet diameter but the rim diameter of the 7.62x39 opposed to the rim diameter of the 308 Win.
There just isn't enough metal there to contain the pressures, without the insert being almost welded to the original chamber. You might get away with one or two rounds but not much more.
Maybe with a very hard, polished stainless insert, maybe.
There would only be around .012 wall thickness for the rear quarter inch or so of the insert. Not nearly thick enough.
However, you could always reload the 308 cartridges "mexican style"
I do this regularly and load accordingly. I use the powder out of three cases to fill the 308 case with enough powder and utilize the .310 diameter bullets, either steel core or lead core.
Velocities and accuracy are very good in a rifle with a 1-12 or 1-15 twist rate. Don't have to worry about the corrosive factor either.
I'm not alone with this practice and I've been doing it for almost 30 years. Started with pulled bullets from 7.62x54R. There just isn't enough difference in the diameters for the actions to notice. Basically the bullets get swaged to bore diameter as they leave the throat and start obturating into the rifling. Do the same with the 30-06 as well.
- Location
- Steel Town
Thanks bearhunter; I was indeed referring to removable inserts. I often use 32 SW and 32 ACP inserts in my old 30-06 for plinking and squirrels. Never stellar accuracy, but 'good enough' for my needs. I often wondered about the do-ability of a 308/30-06 to 7.62x39, but assumed chamber pressures combined with thin chamber insert walls near the rim would create an unsafe/unworkable situation.
I am sitting on some Trail Boss, and I most certainly can load down 308 to reduced velocities. I also like the idea of using surplus bullets and powder for plinking.
I am sitting on some Trail Boss, and I most certainly can load down 308 to reduced velocities. I also like the idea of using surplus bullets and powder for plinking.
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Generally speaking, the over size bullet would undoubtedly cause pressures to spike.
The bullet would have to swage to 308" and probably would affect accuracy.
Like most things do when you ignore basic rules, you will get away with it for a while, until something breaks.
0.003" wont cause an issue with pressure swaging the bullet down. Maybe if you were at max pressure and didnt restart at the starting load when you changed bullets.
It may cause an issue with neck clearance and in turn that will cause a pressure issue but its not the swaging of the bullet
In the cast bullet world 2 or 3 thou over size is desired and will net you lots more velocity before leading happens.
maple_leaf_eh
CGN Ultra frequent flyer
That is scary! But shows the forces present in a chamber.
How many of us load at less than the cartridges potential?
You tell us it's safe then give me two very common reasons it might not be safe.
I don't think there are many 7.62 x 39 reloaders exploring cast bullet options, especially when the OP is asking about a chamber insert.
I assume he just wants to shoot cheaper ammunition, maybe I assume too much?
Neat, but I don't think that's what he had in mind. I wouldn't Locktite a chamber insert into any rifle i cared about.
It sounds suspect to me anyway.
Now you can turn your 308 or 30-06 into a 7.62x39 and
take advantage of inexpensive ammo!
Simply coat the the outside of the adapter with non permanent Locktite™, place a fired 7.62x39 case inside the chamber and close the bolt. After 10-12 hours, eject the 7.62x39 case and you are ready to start shooting. Inexpensive Russian ammo costs 25-50% less than any regular 308 or 30-06. A broken shell extractor will remove the adapter and return the gun to it's original caliber. If you are careful, the adapter is reusable!
Also available in 308/30-06. Each kit includes one tube of Locktite™.
Complete kit: only $25.00. Broken shell extractors: $10.00
