Troy Defense PAR Caliber Question??

74man

There might not be an answer to this question because the rifle is so new but here is my question. I have been reading alot about markings on barrels, especially AR Barrels and everything I read say's that if the barrel is marked .223Rem then that is what you should shoot but if the barrel is marked 5.56mm then you can shoot both .223Rem and 5.56mm! I emailed Troy Defense to ask about what can be shot in the rifle because on the side of the mag well it is printed in white letters .223Rem and the barrel is also marked .223Rem. The response I received said that they marked the rifle .223Rem for marketing purposes and that the rifle will shoot both .223Rem and 5.56mm. It seems to be a strange answer after reading about rifles marked .223/5.56. I would like to have the experts opinion about the markings on the PAR rifle. Do you beleive their answer about the marketing aspect or would you strictly abide by the marking on the rifle and the barrel?[?][?] Do you think because this AR is a pump action, that the breach is capable of firing both? Should I take the rifle to a gunsmith and have him measure the leade before shooting 5.56mm ammo? Since the chamber pressures are so different between the .223Rem and the 5.56mm Nato, am I doing a dis-service to the chamber or should I beleive the email which I got back from Troy Defense and shoot both[?]? I would apprecicate all answers as to what to fire in this rifle. I also wrote Troy Defense with "Attn Marketing Director" about three weeks ago with the same question but so far no response. Thank you, Bob[?]

tsr1965

74man,

The higher pressures of the 5.56 NATO round is not the problem. The problem lies in the chamber throat dimensions. The throat in the 5.56 is a little longer, to accommodate the longer 75to 80, and sometimes 90 grain bullets, fired in service rifle matches. Some have to be single loaded, since they will not fit in the magazine.

If those loads are put into a standard 223 Remington chamber, the bullet will engage the rifling, when chambered. This can, and does create a dangerous pressure spike. A 223 Remington chamber should be fine with bullet weights of 62 grains and under.

Next is rate of twist issues. Those heavier loads mentioned need a 1 in 9, or a 1 in 7" twist to stabilize them. Those are the twist rates most often associated with a 5.56 NATO chamber. Usually the 223 Remington chambers have a 1 in 12, or 1 in 14 twist rate. They will work for bullets up to 60 grains.

Hope this does not add to your confusion.

Best

74man

The Par has a 1-7 twist rate so that means it is a 5.56 rated rifle?
The barrel is marked .223 rem but the twist rate is 1-7, length of barrel is 16". Since it is a pump action, but it has a bolt like an ar15 with the same firing pin, the difference is that the carrier is different and the pump rod. I hope if won't hurt anything to fire 5.56mm cause I have alot to shoot. But then again I have a lot of .223 rem also. I just need something solid to go on, guess I will wait for a letter back from Troy. I will probably give it another two weeks and then I will take it to a gunsmith and have the leade measured.

beantownshootah

IMO, if the manufacturer says the gun is safe with 5.56, the gun is safe with 5.56, and there is nothing else to talk about.

Troy Defense builds quality guns, they're not a company run by idiots, and presumably they know that anyone buying a pump-action AR gun is going to want to shoot 5.56 ammo though it. If you don't trust them to tell you what ammo is safe in your gun, you shouldn't fire the gun!

As above, if you're firing "normal" military-type loads (ie 55 or 62 grain bullets) you shouldn't really have any issues. The 1:7 twist rate also suggest that (despite the barrel label) that the gun is really a 5.56, intended for heavy bullets.

I won't tell you what to do, but if this were me I wouldn't think twice about firing ordinary 55/62 grain 5.56 ammo through this.

Also, this is a long article, but it goes into depth on .223 vs 5.56 and what happens *in the real world* when you fire 5.56 ammo in a .223 gun (quick answer: most of the time, no issue). Its well worth spending the 15 minutes or so to read the thing in its entirety.

http://www.luckygunner.com/labs/5-56-vs-223/

tsr1965

There are also different types of 223 chambers. Some of which will handle those longer bullets. The standard 223 Remington chamber is an example of one that will not. The 223 Wilde chamber which is like a hybrid like is an example of one that will. For the most part, if a manufacturer uses a twist rate of 1 in 12 or 14, the chamber will be a 223 Remington. If they use a 1 in 9 or faster, it will be a 5.56, or in a lot of cases, such as Rock River Arms, they use a 223 Wylde. It has a lesser leade angle than the 5.56, while maintaining the longer throat to accommodate the longer bullets. Is has been proven, that the longer leade angle leads to less projectile upset, and provides better accuracy. In your case, I would ask to speak with a service technician. At TROY that can answer if it has the 223 Wilde chamber, or if it is the Remington version.

Best