I am interested in handloading the Sierra 77 and 80 Gr HPBT MatchKing for 600 Yd competition and have a question about chamber size.  First some info on my AR,,  It is a RRA Lower/NM 2-stage trigger with a Model 1 upper kit fitted with 1:8 20" SST HBAR, free float tube/forend, and chrome bolt assembly.  I ordered it chambered in .223 Remington, which I understand to be the best for accuracy as compared to the 5.56 NATO chambering.  After reading several articles and barrel adds, Wilson in particular, the "Wylde Chambering" stood out as a competition chambering set somewhere in between the .223 Remington and 5.56 NATO sizes to provide increased headspace for the larger bullets.  Now my question/questions are, will I be able to fire 77 and 80 Gr bullets in my .223 Remington chambering, considering they are a little longer than the standard 50-55 Gr stuff, or will I need to have the chamber cut a little deeper "Wylde Chambered" to increase the amount of headspace available?  If I can fire them without having the chamber cut, what would be some of the advantages/disadvantages to Wylde chambering?  It is understood that the larger Grain bullets/rounds will have to be single loaded during slow fire and will not feed through the clip.  

I would appreciate as much  info on Wylde Chambering as I can get to help in my decision.  There doesn’t seem to be a lot of info on this topic.   Thank you.

First of all your terminology regarding headspace is incorrect. Headspace has nothing to do with the bullet itself, it is a dimension that is with the case itself. Increasing the headspace will not allow you to seat a bullet further out, it will create an unsafe condition in your rifle if you do increase it. What you need to increase is the length of the throat. The throat is what dictates the overall length of bullets that are to be seated in your ammo.

The NATO chamber and the Wylde chamber are bascially identical in the body of the case. Where they differ mostly is the length of the throat. The 80 grain Sierra can be seated to an OAL of about 2.550" where the bullet just touches the lands. The Wylde allows for an OAL of about 2.465" with the same Sierra 80. The .223 Remington chamber is even shorter than the Wylde. Since I do not have a .223 Rem. chamber I cannot tell you the exact OAL of it.

The Sierra 77 is designed for magazine length loading and the 80 is not. Also, it is a magazine and not a clip. At 600 yards the Sierra 80 is a better bullet with a higher bc and will also allow a little more powder in the case due to its longer OAL and trying to get closer to the lands. For measuring how long your throat is and trying to get the bullets to get near it the Stoney Point tool is about the best way to do it. This will also tell you if your .223 Rem. throat is too short.

I would be very leery about having the chamber re-cut. If not done correctly you end up with an expensive tomato stake. This is a very critical job and not many can do it correctly.

Most of us highpower shooters are going with the Wylde chamber. It is good for accuracy and good for safe reliable functioning. In highpower a tight chamber will just get you alibis. Accuracy is paramount, but functioning is just as critical. Highpower is not a benchrest game. The 10 ring is fairly large and the biggest variable is not the rifle, but the nut behind the trigger.

Good luck.

Thank you for the information, like I said in my post, there isn't very much information on Wylde chambering.  I'm just getting into the sport and have a lot to learn about the "terminology", but that is why I ask questions.  I think I'll just do the best I can with what I have and see how it goes.  If things go well, I'll get a new upper half and keep the one I have for practice.  

No problem! We all had to learn somewhere and sometime.

The Wylde chamber is a design that was "invented" by Bill Wylde in Illinois in anticipation of the US coming out with National Match ammo in .223 as they did with .308 and .30-'06. Of course they never did and probably will not.

I did have a Winchester model 70 HV with a .223 Rem. chamber and seating the Sierra 80's was done, but they were fairly short in OAL. It can be done, but watch out and make sure you seat them so as to not cram them too much into the lands. Sierras tend to shoot best at about a .010" jump and pressures will rise if seatied into the lands. Get the Stoney Point tool and you will know where to seat them. Also, as the barrel wears the throat will erode and you will have/be able to seat them further out.

P.S. Where in TN do you shoot highpower? There are many good ranges all over the state.

I shot in my first CMP clinic with the M1 Garand on April 19th of this year in Oak Ridge.  The Oak Ridge facility has a really nice 1000 yd Highpower range.  Originally I had hoped to start competing in the Garand class, but after shooting the Garand Left handed, I realized that was not a rifle I ever wanted to shoot again (not that they are bad rifles, but they are not made for left handed shooters).  I started looking to see what everyone else was using and decided to go with an AR in Service Rifle class.  Looks like I was off on the barrel selection, but that can be corrected as I start learning the ropes.  I'm really looking forward to getting some trigger time in and learning a few things.  Right now I'm in the process of breaking in my barrel and sighting it in.

Where do you shoot?

I shoot at Oak Ridge as well.

You made a wise decision to go with the AR over the M1. For the amount of money it takes to make an M1 competitive, you could have about 2 AR's. It is also much cheaper to shoot and easier on the shoulder. We have a several leftys shooting AR's at Oak Ridge and they seem to do well with it.

There are other ranges within decent driving distance. Tullahoma, Chattanooga and reduced course at Cookeville and Columbia.

Welcome aboard.

Thanks,,  Looking forward to getting in and learning the ropes.  I'll see you on the range soon.

You probably could get more responses to your questions on the Competition site under General Topics; however, since Rebel Rifle answered you here, you won't get any better info. He has always been a source of excellent information. What I can't understand is how he got to over a thousand posts and still eats and sleeps. Welcome to Highpower. It's less expensive than Golf and more enjoyable (especially the people involved).

Thanks for letting me know about the competition area. I'll post there next time.  I really appreciate everyone being so patient with the newbe.