Q: My JR Carbine is having feeding problems. What should I do? Feeding problems are almost always traceable to either magazine or ammunition.
The JR Carbine is designed to use either genuine Glock or 1911 milspec-dimension magazines. Aftermarket Glock-compatible magazines or 1911 magazines not manufactured to original 1911 milspec dimensions may not perform properly or consistently. Even genuine Glock magazines have gone through several generations, and they may not all perform the same. See our comparison of two Glock magazine springs.
Not all ammunition is created equal. Although all JR Carbines are manufactured and assembled to the same specifications and tolerances, any individual firearm is likely to tend to prefer one brand or type of ammunition over other, and the JR Carbine is no exception. In most cases the reason is variations in ammunition manufacture - even between lots of ammunition from the same manufacturer. If you are experiencing feeding difficulties unrelated to the magazine, consider trying different types and brands of ammunition to determine which performs best in your JR Carbine.just as with virtually all other firearms. Differences in bullet profile, case diameter, and bullet composition (cast lead bullets are not recommended) can significantly impact ammunition feeding.
Q: When will you offer the JR Carbine in 10mm? The JR Carbine is a direct-blowback design. The bolt is entirely inertial and does not lock when in battery, and the barrel breech does not depress upon firing, so there is no mechanical action to absorb some of the recoil energy as there is in the 1911 or Glock, for example.When the gun is fired the bolt's mass is not enough by itself to sufficiently slow the bolt's recoil, even when using the standard AR-15 aluminum buffer with its own internal sliding weights. In order to adequately slow the JR Carbine's bolt down the bolt in the JR Carbine it has a solid steel buffer to augment the mass of the bolt. Our buffer is significantly heavier than the standard AR-15 aluminum buffer, and is sufficient for the energies developed by the 9mm, 40S&W. and 45ACP. Unfortunately, the full power 10mm generates too much energy (37,500 psi) to accommodate through increased buffer mass within the limited confines of the buffer tube and still permit sufficient fore-and-aft bolt travel for the gun to function. Using a significantly denser material for the buffer - like tungsten, for example - might accommodate the higher power of the 10mm, but it would be cost prohibitive. Using reduced power 10mm cartridges might work, but then the performance would be much like the 40S&W and the advantage of the 10mm would be lost. For these reasons we do not plan to offer the JR Carbine in 10mm (or other high power cartridges such as .357 Sig, .40 Super, or .460 Rowland, for example).
Q: Do you have any plans to make the 9mm compatible with other (Sig P226, Beretta M9, etc.) magazines? We base our JR Carbine model offerings on magazines that have proven most popular among the general shooting public. Currently that means Glock magazines (in 9mm, .40S&W, and .45ACP) and standard 1911 magazines in .45ACP. We have also prototyped an S&W M&P magwell for the .40S&W but will only enter production when we receive an order large enough (about 800 pieces) to justify the tooling and setup costs involved. While there are many fine popular pistols in the market, up to now we haven't had enough call for any one type of magazine other than the Glock and 1911. We are currently evaluating our product mix relative to market demand, and we will continue to consider adapting the JR Carbine to other magazines.
Q: Can I shoot Plus-P (+P) ammunition in my JR Carbine? It should not be a problem for you to use Plus-P ammo in your JR Carbine. We initially prohibited Plus-P ammunition because the JR Carbine is a direct blowback weapon with a non-locking bolt. The added power of Plus-P ammunition caused a significant increase in gas discharge through the ejection port without giving any ballistic advantage over conventionally charged cartridges. We were concerned that the higher power ammunition could cause the bolt to move rearward too soon in the firing sequence, before the chamber pressure had dropped sufficiently, thereby prematurely exposing the case wall and causing potentially dangerous case failures. We have subsequently modified our bolt design and significantly increased the weight of our proprietary buttstock buffer. As a result the bolt stays in battery for a longer period, directing more of the combustion gases into the barrel and out of the muzzle. Plus-P ammunition may or may not provide a significant increase in performance at this point, but it should not cause any problems. We will be modifying our manual to remove the Plus-P ammo prohibition in future printings.
Q: Which aftermarket buttstocks will fit my JR Carbine? There are too many aftermarket stocks on the market for us to maintain a list of all that are compatible with the JR Carbine. However, with the following information you can pretty well determine whether any particular stock you might be interested in will fit your JR Carbine.