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:

1. The drop-in barrels we manufacture for the Ruger 10/22 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
   
2. Our Ruger 77/22 long rifle barrels and the Sako FinnFire sporter contour barrels are chambered with a special reamer of our design that is shorter than the "Bentz" reamer but longer than the match reamer we use for the other bolt action barrels. Almost all unfired ammo can be extracted from these barrels.
   
3. The heavier Sako FinnFire, Anschutz 2007/13 and Remington 504 barrels are chambered with the shortest and tightest reamer. As of November 2003 we are chambering these barrels with a 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.
   
4. 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.
5. The Ruger 77/22 and 10/22 barrels in 17 HMR are chambered using two different reamers. The 77/22 barrels are cut with a 17 HMR match reamer from Pacific Grinding and the 10/22 barrels are cut with a standard Hornady dimension reamer. These two chambers yield the best accuracy and reliability for the action types. As with the 22 WMR cartridge, centerfire cleaning instructions are to be followed. Unfired rounds can be extracted from these chambers.
6. The 17 HM2 barrels for the Ruger 77/22, Sako P94 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.
   
   There is a compromise between throat length, ease of loading and extracting, and accuracy. A short, match-type chamber that engages the bullet in the rifling will generally deliver the best accuracy. Our longer-throat reamer, as used in the Ruger 10/22 barrels, still yields excellent accuracy but the throat does not "grab" the bullet. If you would like to have a bolt action barrel rechambered with this longer-throat reamer we will do so at no additional charge.

   We've made these barrels with the chamber that will deliver the best accuracy but there are precautions to take with tight, short throats. Please be careful and have fun!