Locking lugs in the chamber?

[J E Custom]

Yes my personal experience is that these barrels copper foul very little,

My cousin visited the factory and asked the Morten why they don't lap the barrels to a mirror type finish. Morten said they tried it and found that because the barrel and the bullet were so smooth the pressure went through the roof due to increased friction and the barrel copper fouled very badly.

My favorite barrel maker says the same thing about the finish. His procedure is propitiatory and I talked to him about the best finish, he said the main thing was to get all of the lapping marks to go parallel with the groves and not to polish it to shiny because it would foul worse. He also stated, Never use anything that rotated to lap or polish the bore or chamber.

A nice honed finish like on a chamber was best. His barrels are normally some of the fastest barrels I have used and they foul very little once they are broke in. It is not unusual for his barrel to clean up with two or three patches.

Good to hear that Morten Must have the process figured out. I remember the Marlin's looking very good and needing very little cleaning. I clean often so my barrels are never dirty/fouled so I am not a good judge of how bad a barrel fouls unless it fouls badly in less than 10 or so shots.

Thanks

J E CUSTOM

 

[kiwikid]

My favorite barrel maker says the same thing about the finish. His procedure is propitiatory and I talked to him about the best finish, he said the main thing was to get all of the lapping marks to go parallel with the groves and not to polish it to shiny because it would foul worse. He also stated, Never use anything that rotated to lap or polish the bore or chamber.

A nice honed finish like on a chamber was best. His barrels are normally some of the fastest barrels I have used and they foul very little once they are broke in. It is not unusual for his barrel to clean up with two or three patches.

Good to hear that Morten Must have the process figured out. I remember the Marlin's looking very good and needing very little cleaning. I clean often so my barrels are never dirty/fouled so I am not a good judge of how bad a barrel fouls unless it fouls badly in less than 10 or so shots.

Thanks

J E CUSTOM

J E, It seems that the English link I supplied that birdiemc referred to has used an incorrect terminology and called it micro rifling. Just like you I think of Marlin when it comes to micro rifling and the S&L barrels aren't anything like that.

Looking down a S&L barrel is very similar to looking down a Cooper barrel other than the S&L has a better finish and these minute lapping lines that run parallel to the rifling. Very similar I would say to what you described in your post J E.

Sorry for the confusion!

 

[J E Custom]

J E, It seems that the English link I supplied that birdiemc referred to has used an incorrect terminology and called it micro rifling. Just like you I think of Marlin when it comes to micro rifling and the S&L barrels aren't anything like that.

Looking down a S&L barrel is very similar to looking down a Cooper barrel other than the S&L has a better finish and these minute lapping lines that run parallel to the rifling. Very similar I would say to what you described in your post J E.

Sorry for the confusion!

No worries
I like to hear about other methods and designs. all I can offer is my experiences with things like this and they may be different than others, Interestingly though I do agree with the number of rifling increasing as the bore gets larger.

I have had the best accuracy in big bore rifles with 8 groove barrels(Over .400), 5 or 6 groves have worked well for intermediate calibers, and 3 or 4 have worked best In
.177 to 6mm for me. The height of the rifling is normally determined by the barrel maker and the process he uses. The Micro groove does have the potential for less jacket damage and better engraving. ( That could also be because most of the micro groove rifles made were for pistol cartridges that had thinner jackets for slower speed performance.

J E CUSTOM

 

[MNbogboy]

Could foresee a barrel/receiver one piece in a factory rifle. Possible cost savings with modern CNC/robotic lathe/mills.
Imagine a throw away rifle as a tomato stake in your garden!

 

[LRMonkey]

Could foresee a barrel/receiver one piece in a factory rifle. Possible cost savings with modern CNC/robotic lathe/mills.
Imagine a throw away rifle as a tomato stake in your garden!

Well, that is the new Steyr bolt-action, barrel&receiver is a one piece construction.

 

[MNbogboy]

Well, that is the new Steyr bolt-action, barrel&receiver is a one piece construction.

Wow, that one is no tomato stake at over $5000 US.....my thought was cutting production costs...lol

 

[LRMonkey]

No worries
I like to hear about other methods and designs. all I can offer is my experiences with things like this and they may be different than others, Interestingly though I do agree with the number of rifling increasing as the bore gets larger.

I have had the best accuracy in big bore rifles with 8 groove barrels(Over .400), 5 or 6 groves have worked well for intermediate calibers, and 3 or 4 have worked best In
.177 to 6mm for me. The height of the rifling is normally determined by the barrel maker and the process he uses. The Micro groove does have the potential for less jacket damage and better engraving. ( That could also be because most of the micro groove rifles made were for pistol cartridges that had thinner jackets for slower speed performance.

J E CUSTOM

I do recall that older Sako rifles had microgroove rifling and there were very mixed opinions about accuracy, especially in faster small diameter calibers ie. .222Rem.

 

[birdiemc]

Well, that is the new Steyr bolt-action, barrel&receiver is a one piece construction.

Gonna have to check that one out...I was thinking like MNbogboy that it would be a low end move

 

[hunter0528]

What you have suggested is fairly common in some of the European countries where the number of rifles they are allowed is restricted. By having one action and say a standard and a magnum bolt it is possible to have several different cartridges and calibres.

Blazer, Sauer plus Schultz and Larsen offer switch barrel rifles. The below photos are a Schultz and Larsen cut rifled barrel machined to fit a 6 lug Sauer 202 action. This one is 6.5x55 Swede but I have 223, 22-250, 25-06 and 6.5-284 barrels as well

The actions are steel and the barrel is held into the receiver by either 2 or 3 cross bolts normally tightened to between 62 and 70 inch lbs.

If I remove the barrel and then reinstall it I find that the POI usually changes only .5 MOA.

View attachment 170158 View attachment 170159 View attachment 170160 View attachment 170161

I have a Blaser R8 and the lugs are in the barrell. As you mentioned the change of impact is negligible. The locking lugs in the Blaser are rotary, when closed they expand and cover the entire rear of the barrel, not 3 to 6 points of contact

.

 

[birdiemc]

I have a Blaser R8 and the lugs are in the barrell. As you mentioned the change of impact is negligible. The locking lugs in the Blaser are rotary, when closed they expand and cover the entire rear of the barrel, not 3 to 6 points of contact

View attachment 173013.

That's very interesting. Not quite as beefy looking as most, but I suppose it must be strong enough since it's in production.

 

[Mram10us]

A nice honed finish like on a chamber was best. His barrels are normally some of the fastest barrels I have used and they foul very little once they are broke in. It is not unusual for his barrel to clean up with two or three patches.
J E CUSTOM

How could something that is super smooth allow more fouling? It would seem it has nothing to grab onto?

 

[Mram10us]

I have a Blaser R8 and the lugs are in the barrell. As you mentioned the change of impact is negligible. The locking lugs in the Blaser are rotary, when closed they expand and cover the entire rear of the barrel, not 3 to 6 points of contact

View attachment 173013.

That is really cool. Never played with one of these. THanks for teaching me something!

 

[John Klingenberg]

The M-60s we had in the military had a setup similar to an AR where the lug recess was threaded to the shank of the barrel then pinned and soldered. Except is was a two lug bolt. With today's precision machinery it could be accurate.

 

[birdiemc]

The M-60s we had in the military had a setup similar to an AR where the lug recess was threaded to the shank of the barrel then pinned and soldered. Except is was a two lug bolt. With today's precision machinery it could be accurate.

I've never seen one in person, looks like the middle picture you can see the pin you mentioned am I correct?