Ptg pull through chamber reamer

[freebullet]

So, it showed up today. Never used one of the pull through style. Seems purty straight forward. Excited to fix or ruin & replace the offending barrels. These both show promise but require small base die screwed down tight. I did get the drive rod & intend to take it slow by hand.

Anyone used one?
Any tips to share?

 

[Ian]

I read a lot about them on the M-14 forum. Use real cutting oil, don't ever turn them backwards, clear the chips more often than you think you need to, all the stuff you already know.

In general, chambering reamers will cut .000000001" depth per turn until the last thousandth to make headspace....and then take .005" per half turn (Murphy's Law). If your barrels have the black nitride coating inside the chambers it will instantly ruin a HSS reamer.

 

[freebullet]

Ha, yes by that method I need only a eighth to a quarter turn in the one. It showed up strapped & wrapped to a board in a box. Well done by Pacific tool & gauge.

Did some initial shim tests. Placed foil between barrel & receiver face to gauge how far out a slowly eased in case was off. I was able to change the headspace that way but didn't fire. Measuring the shims it's off .001 on the pistol barrel and that matches the sized & measured brass chamber tests.

I've grown accustomed to using 10/30 with the throating reamers. The cutting oil let them bite to much for my taste. Only drawback I found was the chips wanna stick & you have to clean more.

I did a couple throats with nitride. The one Swenson bbl had some really tough stuff. The lone wolf tough but not as thick. Didn't dull the reamer but I went slow, by hand, & cleaned every few turns. It took 3 hours.

They will sharpen the reamer to, unless we get really crazy it shouldn't be ruined. We'll see, one is stainless, one is supposed chromoly.

 

[Ian]

SS (inless Ruger SS!) and CR both ream like butter in my limited experience. You got this.

 

[freebullet]

Did the stainless one last night. 12 turns & done. Took 6 turns to get to minimum 1.463 & another 6 to 1.465. Should be good to try live now.

Other one does look like nitride. We'll see....

Reamer & chip porn-

 

[Kevin Stenberg]

If an individual has no experience doing this kind of chamber adjustment. Where could i go to read or watch how and why to ream a throat.

 

[freebullet]

Kevin
There was a good thread about throat reaming on the old bullet board but I'd guess the photobucket fiasco eliminated the pics. Throating a pistol is different than revolver cylinder throat reaming & chamber reaming. It might be best to research them seperate.

There are a number of different reamers for correcting various issues. In these barrels I am trying to correct them being short chambered. Problem is they won't chamber standard off the shelf ammo or any ammo that isn't below minimum spec for headspace.

This case as example. 1.463 is the minimum headspace for 223 & 5.56. The stainless barrel wouldn't freely chamber rounds more than 1.460ish. A 223 no go is 1.466 & field @ 1.469 iirc. The mil 5.56 min is 1.463 & the max is 1.473. I was trying for 1.465. Should allow any regular ammo & most mil surp ammo to fit too. The one I did should slam home on 1.467-9ish meaning this gun shouldn't stumble with anything but the longest loads.

They were likely chambered with a chamber rougher & never finished properly. This pull through style cuts the whole chamber & throat. It is specific to use with on assembled ar barrels. With the extractor & ejector removed the bolt rides a bushing putting pressure against the reamer which is driven from the muzzle end. As soon as the bolt closes you've reached minimum (1.463 in 5.56) and you can adjust the depth of headspace to your desires from there.

A regular chamber reamer would be used from the chamber end usually in a lathe.

The pistol throating reamer is used to correct the throat leade only. A chamber finish reamer can do this but I speculate most budget & even some not budget minded barrels get done with a chamber rougher but not finished. Have any guns that require loads seated much deeper than books call for? Those are likely throatless wonders.

The problem that creates is ammo pickyness & general unreliability. Sure we can make ammo fit but universal loads are out of the question unless loaded for that short chamber. Seating deep can increase pressure so many shooters throat to load longer for pressure reduction to achieve a higher power factor with a small caliber. More space to use basically.

I've heard it said don't throat to fit your ammo, make ammo fit the gun. Trouble is throats are all ober the place & leaving it doesn't resolve the fact that throatless wonders are going to be ammo picky. They'll only like the short loaded stuff or in the case of short chambers only chamber the minimum spec stuff.

For me it's done to correct those issues to make the piece in question reliable & function with any standard for caliber ammo. This becomes increasingly important when loading for half a dozen guns that all need to use the same standard ammo.

The alternative would be custom ammo for every gun. Hope any of that helps ymmv!

 

[Ian]

There should be a thousandth or two clearance between the longest SAAMI-spec ammo and shortest chamber. Gun manufacturers toward the long end of the spec and ammo manufacturers the opposite, so the tolerance is typically quite wide. Sometimes though, not so much.