Chamber Info

Important Chamber Information for .22 Long Rifle, .22 WMR,    .17 HMR & .17 HM2 Drop-in Barrels

Our rimfire drop-in barrels have been chambered with a special match-type chambering reamer. In keeping with the all the manufacturing processes we use, the chamber was machined with a precision match reamer. This means that the barrel will deliver the type of accuracy you expect from a Lilja barrel.

Caution: this also means that some ammunition causes the bolt to close with resistance and that you may have difficulty removing an unfired round from the chamber. Always keep your rifle pointed in a safe direction while chambering or removing a loaded round.

We use several different chambering reamers in making our .17 and .22 caliber drop-in barrels. The reamer used depends on the type of barrel and action it will be installed on. The different types are listed below:

Semi-auto and Bolt Action .22 Long Rifle

The drop-in barrels we manufacture for the Ruger 10/22, Ruger 77/22, Sako FinnFire, Sako Quad are chambered with a “Bentz” semi-auto match reamer and it is not as short as the other match reamers we use. Unfired ammo can be extracted from this chamber. We do not recommend using CCI Velocitor or Stinger ammo in the 10/22 barrel. Also see this FAQ on the subject – Click Here

CZ 455’s

Our newest CZ 455’s 22 LR’s are chambered with my new ‘Lilja 2’ reamer, which is a modified version of the previous Lilja reamer. It still engraves on the bullet, but allows you to remove unfired ammo from the chamber. This chamber was designed around the Ely EPS ammo.

Anschutz 2007/13 barrels

These barrels are chambered with the shortest and tightest reamer made by Pacific Precision Grinding that is designated as Eley EPS Match. This reamer cuts a chamber that is about .2255″ in diameter after polishing and it has a 2º per side throat angle. The throat from this chamber will engage the bullet on most ammunition. Besides the Ely EPS ammo it works very well with the target ammo available from other manufacturers. With this chamber the caution above applies. Also note that these receivers are designed so that the headspace can be adjusted. It is required to use a standard Go Gauge when installing these barrels. We offer for sale a .043″ Go Gauge made by Pacific Precision Grinding.

.22 WMR

The Ruger 10/22 barrels in .22 WMR (rimfire mag) are chambered with a semi-match type reamer. It does not engage the bullet so tightly that an unfired round cannot be removed. The 77/22 .22 WMR barrels are chambered with a Pacific Precision Grinding match reamer. The .22 WMR barrels are also made to .224 centerfire dimensions not rimfire diameters. And because the bullets for the .22 WMR are jacketed, centerfire cleaning and break-in instructions apply.

.17 HMR

The Ruger 77/22 in 17 HMR are chambered using a 17 HMR match reamer from Pacific Grinding. As with the 22 WMR cartridge, centerfire cleaning instructions are to be followed. Unfired rounds can be extracted from these chambers.

.17 HM2

The 17 HM2 barrels for the Ruger 77/22, Sako P94 & Quad, CZ 455 and Remington 504 are chambered with a Pacific Precision Grinding match-type reamer. Like the 22 WMR and 17 HMR cartridges, centerfire cleaning instructions apply due to the jacketed bullet used in this cartridge. Unfired rounds can be extracted from this chamber. The 17 HM2 chamber will fire 17 Aguila ammo.

Please be careful and have fun!

rimfire ammo