6 PPC in an AR 15

[mike in co]

well there are ar's and there are ar's
i have posted for over TEN YEARS on the work i have done with three ar's
one is 223 rem in a short throat min spec case....shoots right at 0.2....1/14 twist hart 3" wide flat fore arm/36x brd luepold..took me years to get there...oem 8208 was the final powder.
one is 308win br...1/15 twist krieger 3" wide fore arm 36x luepold.....small is 0.116" shoots right at 0.2 also bib 134's n140 powder
one is a 6 beggs..and is still in work......
the 223 can do semi auto..the 308 could but has a blocked gas port.
the 6beggs has no gas port single shot only with a side charging bolt handle.

so do not say it cannot be done.....no zero's a few 1's...
now that i am semi retired i plan to do more work with them..they have sat for the last 4 yrs....

mike in co

 

[jlcprec]

If I do a 6mm on a .223 case, I can run higher pressures than with a PPC case? That sounds interesting. The .223 case has similar capacity compared to a PPC, I know it doesn't have the accuracy potential, though.

When you drill the hole for the gas port, do you try and put it in a groove, or not worry about that? What about a burr inside the barrel after drilling? I was thinking of sliding a bullet up the barrel and drilling into that when drilling the gas hole.

What kind of velocities can be had with a .223 and 52 grain bullets from a 20 inch barrel. With a .100 short .22 PPC 3500 is easy. Can a .223 come close to that? I also have used .22 barrels.

Jim

 

[mike in co]

i do 3500/3600 with a 26" BBL WITH 52/53 GR
as far as the port..drill small and use a reamer to open...
nothing wrong with a support under the hole....lead slug ??
you can use a bolt on gas block with allen screws as a guide...one screw to hold in place...and drill thru other screws to use as guides...multiple screws/mulitpe size holes..
not my ideas but given on this forum by others...
mike in co

If I do a 6mm on a .223 case, I can run higher pressures than with a PPC case? That sounds interesting. The .223 case has similar capacity compared to a PPC, I know it doesn't have the accuracy potential, though.

When you drill the hole for the gas port, do you try and put it in a groove, or not worry about that? What about a burr inside the barrel after drilling? I was thinking of sliding a bullet up the barrel and drilling into that when drilling the gas hole.

What kind of velocities can be had with a .223 and 52 grain bullets from a 20 inch barrel. With a .100 short .22 PPC 3500 is easy. Can a .223 come close to that? I also have used .22 barrels.

Jim

 

[mwezell]

If I do a 6mm on a .223 case, I can run higher pressures than with a PPC case? That sounds interesting. The .223 case has similar capacity compared to a PPC, I know it doesn't have the accuracy potential, though.

When you drill the hole for the gas port, do you try and put it in a groove, or not worry about that? What about a burr inside the barrel after drilling? I was thinking of sliding a bullet up the barrel and drilling into that when drilling the gas hole.

What kind of velocities can be had with a .223 and 52 grain bullets from a 20 inch barrel. With a .100 short .22 PPC 3500 is easy. Can a .223 come close to that? I also have used .22 barrels.

Jim

Jim, I usually do a cerrosafe cast in the bore where the port will be drilled. Drill it in two steps...the first being just a few thou short of final size. The last will just have to remove very little metal and will take most of the burr with it from the first step. It's debatable, but I don't worry about the hole being in a land or groove. I've tried it both ways and can't tell a difference, and it's a real pain to set up for putting it in a groove, that starts from the get go..chambering, indexing the barrel extension, etc. It's going to copper some either way and the edges of the hole will erode over time, either way. It's going to shoot..either way. And with a pound of reciprocating mass slamming back and forth in a gas gun, with a flimsy upper receiver to which the barrel mounts...I doubt either of us could shoot the difference in where the hole is. We worry about getting perfect BR barrels, but with AR's, we drill a hole somewhere in em' and they still shoot pretty darn well!
You know how velocities go. Lots of variables. I usually load for about 3100 from a 20" barrel with 52-55 grain bullets.(.223)

 

[alinwa]

The inherent accuracy of the 6PPC cartridge is completely lost, once you place it in a magazine, because you'll never be able to tune it to it's maximum capability. Finding the load is one thing, tuning it is another.

Seating depth is eliminated by the requirement that it fit inside the magazine. .001" difference in seating depth can make a world of difference when trying to put a bullet through the same hole, shot after shot, which is what the 6PPC is capable of.

OK ab, you asked for it......

The inherent accuracy of the 6PPC cartridge is completely lost, once you place it in a magazine,

This is utter garbage. The idea that placing an "inherently accurate" round into a magazine somehow destroys it's accuracy potential is laughable.

because you'll never be able to tune it to it's maximum capability.

Explain to me ab exactly how it's "no longer tunable?" BTW, here's what I do. I tune first, THEN I place the round in the magazine....... voilahhh!! A tuned round, IN THE MAGAZINE!

Finding the load is one thing, tuning it is another.

I have no idea what "finding the load" means, but then I shoot truly accurate rifles using good components. I hear this sort of talk from factory rifle shooters using factory dies

tuning it is another.

"tuning is another"............... obviously something you've NEVER DONE! (BTW, You can't "tune" an AR rifle using .001 seating depth changes, with or without a magazine. No AR will show a difference between .001 changes IMO. They're simply not accurate enough....)

Seating depth is eliminated by the requirement that it fit inside the magazine. .001" difference in seating depth can make a world of difference when trying to put a bullet through the same hole, shot after shot, which is what the 6PPC is capable of

Several items here to illustrate your lack of experience.... #1, "seating depth is eliminated." Yeahh right, HOW is "seating depth eliminated?" I'm going to guess that what you actually mean is, "the ability to vary the seating depth is eliminated"........ This doesn't make any SENSE but I'm guessing it's what you mean. I routinely vary the seating depth of magazine-fed rounds. How could you possibly believe that the magazine affects seating depth? Do you OWN a magazine rifle? If you do, try this liddle experiment, VARY THE SEATING DEPTH! Now write down what happens! wheeee...... #2, ".001" difference in seating depth can make a world of difference" and blahh blahh blahh.... Do you own a PPC BR rifle? "trying to put a bullet through the same hole shot after shot?" If your rifle DOESN'T "put bullet after bullet through the same hole shot after shot" tuned or untuned it's got serious problems! "Tuning" using fine adjustments like "001 seating depth" is about the SHAPE of the hole, you don't "find a load" or "tune using .001 seating depth" to get one-hole accuracy........ You get one-hole accuracy in the build and in the gross adjustments. You can spend the rest of your like varying seating depth a thou at a time trying to find the hole. You won't


But all that aside, please describe to me exactly how "a magazine" keeps you from "making the necessary .001 changes in seating depth" that you feel are part of tuning.

I'm lissening.....



al

 

[flatlander]

When Krieger sells an AR15 bbl, they set it up so the gas port is in the middle of a groove. At one time, I thought there might be some importance attached to the port location relative to lands & grooves, but a discussion over dinner with John Holliger at the SHOT Show a few years ago convinced me to stop worrying about it. To date, I've done only a few AR15 & AR10 bbls; once or twice, I guess I got lucky and the port wound up pretty much centered in a groove. However, as Mike mentioned, it really doesn't seem to make any difference. I drill a 1/16" pilot hole, then enlarge to finished dia. with a succession of larger # drills. That doesn't leave much of a burr, but I can see that the use of a lead slug could be a worthwhile method of minimizing burring.

Any of you who follow the NRA High Power game will know that the National Championships have been won several times in recent years by a fellow named Carl Bernosky, shooting an AR15 spacegun chambered for the 6 HAGAR, which was originally derived from formed & trimmed 30 Rem brass, and which has a casehead dis. of .415", same as the 6.8 SPC. This cartidge is longer than the RAT, which limits the bullets that can be magazine fed, but it's also a very accurate round. I had a couple of HAGAR match rifle uppers built by John Holliger, and spent hours forming & trimming over 1200 pieces of brass for them. The thing that kept me going was the story that commercially available brass was 'just around the corner'. I finally gave up on that fairy tale, and sold off the newer of the two uppers, plus most of the brass, and the custom Redding die set. However, Hornady has been sponsoring Carl and is now making brass & dies for the HAGAR. Holliger no longer chambers barrels for the RAT, simply because of a number of complaints about broken bolts. However, he's comfortable chambering for the HAGAR, I would guess due entirely to the greater strength of the SPC bolts. I've still got one HAGAR upper, and am thinking about getting some the Hornady brass & a die set. It's a good round, perhaps the best 6mm AR round.

Keep in mind, I'm talking about accuracy good enough to clean the NRA HP targets, which have X-rings measuring 1 MOA - not benchrest accuracy standards. And if a particular 6mm round doesn't give me at least some advantage over the 223's ballistics out to 600yds, I'm not interested, simply from a practical standpoint. That doesn't mean I'm looking down my nose at someone who simply wants to experiment with a 6mm cartridge in the AR platform - it'd be a fun project, and I'd encourage the OP to keep looking into it.

 

[AeroE]

Now my next thought is, why not just get a 6mm/.223 reamer, and avoid the feeding issues? I can use the same bolt and magazines that I already have. What are the issues with this cartridge? I know it won't be as accurate as a PPC, but I have plenty of PPC's if I really want to try and put the bullets into the same hole. If I could make an honest 1/2 to 3/4 inch rifle with a 16x scope off a rest at 100 yards, I would be very pleased.

JIm

Shoot good bullets through good barrels for good accuracy. I wouldn't worry much about matching the PPC, its accuracy depends on more than just the cartridge, the whole package has to be considered.

Anyway, the 6X45 or 6-.223 has been around a long time. Published load data seems to be conservative compared to reported real world speeds.