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AR upper in 6 PPC.

chiefrchiefr Member Posts: 10,964 ✭✭✭✭
Have a chance to buy a complete custom upper in this cal. Heavy barrel 24". The seller has never fired it.
All the BR guys are using 6 PPC bolt guns these days. Never heard of an AR in this cal but, dont see why not since the 6.5 Grendell, and 7.62x39 share the same case. 

My main concern would be with crimping bullets. Having been around semi autos particularly ARs for years, I will never shoot ammo that is not crimped. Been reloading near 50 years and always crimp any ammo I feed in  semi autos.  Have personally seen the negative affects of firing not crimped bullets in semi auto bullets more times than many. Been in a number of heated debates over the subject of crimping and autos.

Any thoughts here? I dont think anyone makes a separate crimp die in this cal. Accuracy potential inputs? 

Comments

  • MobuckMobuck Member Posts: 11,480 ✭✭✭
    Finding bullets with a cannelure may restrict your choices. If you want to crimp, go for it. Most of the .223 I load for AR rifles is crimped but I'm certain that most of the factory loaded varmint ammo I shoot isn't crimped and I haven't had any problems.
  • rufe-snowrufe-snow Member Posts: 18,452 ✭✭✭
    i've been using Lee's factory crimp dies for years. With good results. Even without a crimping groove, it's possible to get a tight crimp on jacketed bullets.  

    If they don't make a factory crimping die for the 6 mm PPC? It might be possible, to jury rig one of their other 6 mm or .243 factory crimping dies. So that they might work?

    Recently I had to do that, with a Lyman .223 "M" die. For seating 40 grain bullets, in Armscore  22 TCM brass. 
  • nononsensenononsense Member, Moderator Posts: 10,573 ******
    Have a chance to buy a complete custom upper in this cal. Heavy barrel 24". The seller has never fired it.
    All the BR guys are using 6 PPC bolt guns these days. Never heard of an AR in this cal but, dont see why not since the 6.5 Grendell, and 7.62x39 share the same case.
    The 6PPC is a very high pressure cartridge so consider all of the variations in reloading carefully. 6PPC cases are derived from the 220 Russian case. While this may seem to make no difference, it's the interior design of the case which has a major impact on the cartridge designation. This cartridge will feed properly from several variations of magazines.

    Does the seller have a copy of the chamber reamer print?
    There are probably 20 different reamer designs used for this cartridge. The all encompassing use of this cartridge for competition often resulted in shooters wanting to make small changes in the reamer design trying to finesse the accuracy. If you don't have a print, I suggest casting the chamber or having your gunsmith handle it for you. You need an accurate representation of the chamber, especially the neck diameter for safe reloading.
    For competition, almost all 6PPC shooters are using 60-70gr match bullet. None of these custom or factory bullets have a cannelure because this feature seriously compromises accuracy when groups are measured to 0.0001" in competitions. Reloaders control the grip on bullets by using neck tension as this can have a serious effect on accuracy. Finding the proper amount of neck tension for your chamber and bullet will result in best accuracy.

    Lee makes a separate crimp die for the 6PPC. Redding's seating die will crimp also. So if you do choose to use bullets with cannelures, you can control the crimping.

    You'll need to measure the twist rate of the barrel in order to find the range of bullets which will stabilize in your barrel.
    Do you know the gas tube length of the barrel? Is it a Carbine, Mid-length or Rifle length? A 24" barrel should be rifle length but check it anyway just to be sure. For high pressure cartridges, we have been using the +2" gas port length since it smooths out the pressure curve and improves accuracy.

    Best.







  • chiefrchiefr Member Posts: 10,964 ✭✭✭✭
    edited July 17
    Thanks, RS and NN, Did not think of a chamber cast but have plenty Cerrosafe. My biggest problem with ARs is the limited COL due to the mags. Takes a considerable time working loads when you have limited COL, but I have been successful with 308, 223, and 6.5 CM. 
    6 PPC is a new challenge. My concern as away is the bolt slam and Newtons law: Bolt slam moves case forward;  bullet resists forward momentum. Have seen an upper split and shooter taken to ER and have a considerable amount of stitches on fingers and hand. Shooting 190gr SMKs out of an AR 308 w/o crimping bullets.....bad idea.

    Another concern with ARs is they like FL sized brass over NSO. 
      
    As mentioned in OP, crimp at least to me is a must and would have to be a subject of experimentation with different degrees.
    The Lee FCDs have been God send in my endeavors to gain max accuracy out of ARs. I trust them to eliminate bullet setback.   Did not know Lee made one in 6PPC and will check it out.

    Seller adding plenty of Norma Brass and RCBS dies to add at no extra cost.  Twist unk, but I can check myself. Barrel length is 24" rifle length tube. Seller is a BR guy and well known in my state but having to quit as age taken the best of his eye sight.


     
  • bpostbpost Member Posts: 30,964 ✭✭✭✭
    I use a taper crimp on all AR ammo I load, I have never had any bullet setback while chambering a round, YMMV.
  • MobuckMobuck Member Posts: 11,480 ✭✭✭
    Read the chamber designation carefully. 6mm PPC and 6mm PRC look a lot alike.
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