Gunsmithing LR-308 barrels ???

[tipper]

Well I've got 3 new LR-308's, a 16" 18" an 20".
I did chamber cast of each barrel, don't like what I found, the barrels all seem to be made & chambered by the same MFG.
The 16" barrel chamber has .200" of free bore at a OD .316 at almost no lead angle at the lands .308", the case neck an shoulder have no definitive lines they just roll onto each other, brass will grow like crazy.
The 18" barrel chamber has .180" of free bore, the rest looks like the 16".
The 20" barrel chamber looks like the 18".

I've done cast of other chambers on bolt rifles have never found the free bore to be so over sized, even on well used rifles. Just don't think anybody is doing QC these days.

 

[tipper]

will pic help, or is everyone doing a cast of there chamber, the free bore area to the shinny ring is the area that is over size.
Fired 308 case & 3 chamber castings

16"

18"

20"

 

[fastshooter03]

I would hope that more expensive barrels would have better chambers compared to the Dpms types so you get what you pay for?
I'm sure the high volume mfgs want less problems(high pressure signs, etc) so they make them big and state that their barrels may or may not shoot well.

 

[tipper]

I would hope that more expensive barrels would have better chambers compared to the Dpms types so you get what you pay for?
I'm sure the high volume mfgs want less problems(high pressure signs, etc) so they make them big and state that their barrels may or may not shoot well.

This are not low end dpms types

 

[InkedIan]

This are not low end dpms types

Who's are they?

 

[tipper]

Well I bought these rifles on there fit an finish that I could see a the time, I did not order them sight unseen. What you can not see should be of the same fit & finish & not out of spec. for a new gun. If these barrels were not built by the same MFG. then the reamer used was from the same MFG. Is there no one that has seen this.

 

[fastshooter03]

Sorry, when I see somebody use LR-308 I assume they are DPMS factory barrels.
At least you're able to cast chambers and know what you have.
I don't think there are that many people doing that.
I use a 308 match reamer but only for myself or if requested.

 

[tipper]

I have a couple or so on rifles that are of match grade that I did the same thing to when I first got them. I'm not going to have a gun that just goes bang. The condition of the chambers in these rifles, I feel will not help in the accuracy of these rifles. When I get them to the range the target will tell the truth.
This leads me to believe there are few parts MFG. & a lot of parts installers clamming to be MFG.

 

[tipper]

Really is this over every ones head, DA

 

[bohem]

Have you shot them? I see the measurements and I understand that you could be concerned but I must be missing your point unless it was to detail the discrepant quality control...

If they shoot well, does it matter?

 

[tipper]

As the throat wears in length & diameter the psi on the bullet is reduced, by the volume increase or by the gases that pass by the bullet before it seals in the bore. From shot to shot this will vary widely. I have not found any reamer specs. that match the specs. that I found in these New Barrels.

.308 Palma Match
Shank 0.4370
Base Diameter 0.4690
Shoulder Diameter 0.4550
Neck-1 0.3400
Neck-2/Case Mouth 0.3400
Freebore Diameter 0.3085
Pilot Diameter 0.2970
Min. Chamber Length/Base-to-Case Mouth 2.0200
Base-to-Shoulder 1.3540
Neck Length 0.3090
Freebore Length 0.0750
Rim/Belt Thickness 0.2000
Shoulder Angle 20*
Throat 1.5*

.308 Win commercial
Shank 0.4370
Base Diameter 0.4700
Shoulder Diameter 0.4550
Neck-1 0.3462
Neck-2/Case Mouth 0.3442
Freebore Diameter 0.3100
Pilot Diameter 0.2990
Min. Chamber Length/Base-to-Case Mouth 2.0250
Base-to-Shoulder 1.3540
Neck Length 0.3210
Freebore Length 0.0900
Rim/Belt Thickness 0.2000
Shoulder Angle 20*
Throat 1*45”

7.62 NATO
Shank 0.4670
Base Diameter 0.4725
Shoulder Diameter 0.4560
Neck-1 0.3460
Neck-2/Case Mouth 0.3460
Freebore Diameter 0.3110
Pilot Diameter 0.2990
Min. Chamber Length/Base-to-Case Mouth 2.0250
Base-to-Shoulder 1.3560
Neck Length 0.3200
Freebore Length 0.1500
Rim/Belt Thickness 0.2000
Shoulder Angle 20*
Throat 2.5*

M852 precision military chamber
Shank 0.4370
Base Diameter 0.4700
Shoulder Diameter 0.4550
Neck-1 0.3430
Neck-2/Case Mouth 0.3430
Freebore Diameter 0.3095
Pilot Diameter 0.2990
Min. Chamber Length/Base-to-Case Mouth 2.0200
Base-to-Shoulder 1.3540
Neck Length 0.3120
Freebore Length 0.0750
Rim/Belt Thickness 0.2000
Shoulder Angle 20*
Throat 1.5*

The closest too the Wylde is the M118 Obermeyer Match. This is what little info I could find on the Obermeyer.
Base Dia. .473
Shoulder Dia. .455
Neck @ shoulder .344
Neck @ mouth .344
Neck lenth. I assume is in the middle of 7.62 Nato and M852 at .315
Freebore Dia. .3085
Freebore lenth .3085
Pilot Dia. .299
Base to case mouth. 2.02
Base to shoulder. 1.354
Head lenth from base. .200
Shoulder 1/2 angle. 20*
Leade Angle. 2.5*