Quote:
Originally Posted by Al Nyhus
Virtually all real 22RF 'match' and BR chambers force the driving band of bullet into the rifling when the bolt is closed.....they don't just 'plunk' into the chamber like a normal 22LR does.
The amount of rifling engagement differs as these specialized chambers are done for specific ammo. That's where swapping ammo back and forth in chambers on real-deal 22LR target rifles can at times pose a problem.
It's probable that there's nothing whatsoever 'wrong' with the chamber. Be aware that these target chambers may require the occasional use of a toothed little tool to remove the carbon and leading in the throat with "may" being the important word, here.
Inspecting the chamber/throat with a borescope and identifying and correcting any cleaning-related issues is the first thing to do. If you have any questions, get the gun into the hands of someone that knows RF target chambers and builds these guns to help you out.
These guns are specific and extremely specialized. Leave any nail setters, punches, hammers, trowels, etc. in the toolbox.... 
This chart shows just a few of the different reamers that PTG has for specific ammo. There are many, many more variations! You can easily see the significant differences that can give issues when mixing different ammo and chambers:
Good shootin' -Al |
Al, with all due respect… I know you’re an informed guy but, some facts.
Those little toothed cutters made by Frank Tirrell never worked even back 20 years when he sold them and nobody really ever used them. You want a couple never used ones I’ll send’em to you.Don’t need them anyway since C4 will take that ring out with a 15 minute soak and zero brushing in the throat.
Lastly, several BR smiths don’t chamber to engrave but bump the drive band or minimally engrave, but a long ignored carbon ring is easilly attended to these days. Also, lots of top flight smiths don’t chamber to a set depth, based on several factors including barrel configuration, the black art of RFBR gunsmithing.
Finally, the Lapua only, or ELEY only chambers are largely a myth, while some smiths do make chamber adjustments, most of the active top flight shooters laying down big target numbers, now shooting Lapua, are doing so with guns that were previously only shooting ELEY. The exceptions to this might be for guys shooting real short or long(ish) chambers in MI barrels. There is a pretty good OAL variance between lots of top flight ammo….sometimes over .010” This is pretty much why a certain “ self important” Kentucky RFBR smith used to endlessly drone on for ELEY to publish OAL data with their lot info.