I have considered the 6 PPC but the brass is expensive and hard to come by. The 6 ARC is very similar in size plus there is a lot of data for light bullets. What recommendation do you have about chamber dimensions, barrel twist and barrel length? Shooting club matches at 100 yards. Thanks for your input
Hi Oldman726,
6 PPC is still the “default answer” for 100/200-yard benchrest-style accuracy, but I also see plenty of people choosing 6 ARC when they want easier brass availability, lots of published data, and the option to run a wider bullet range (especially if they already like the Grendel/ARC-sized actions and mags).
From the research I’ve done looking at what others have to say on different forums:
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Chamber: If you want factory-ammo compatibility, stay close to SAAMI. If it’s a dedicated match bolt gun and you already know your bullet, people often talk about a custom throat/freebore tuned to that bullet/seating depth (noting SAAMI freebore is discussed as ~0.0899").
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Twist: If there’s any chance you’ll try 105–110s later, the most common “safe” advice I see is 1:7 or 1:7.5. If you’re truly staying lighter, many report 1:8 working fine even with 108s in some rifles.
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Barrel length: For 100-yard use, I mostly see people choosing based on the build, with a lot of examples around ~22" (not a rule, just common in posts).
Here are links to the different topics I found touching on these concepts:
AccurateShooter – 6mm ARC Practical Reloading:
https://forum.accurateshooter.com/threads/6mm-arc-practical-reloading.4010344/
AccurateShooter – 6ARC Barrel Twist thread:
https://forum.accurateshooter.com/threads/6arc-barrel-twist.4042651/
AccurateShooter – Reloading 6mm ARC Prelim (SAAMI freebore discussion mentioned):
https://forum.accurateshooter.com/threads/reloading-6mm-arc-prelim.4023449/
Rokslide – 6mm ARC Lightweight Backpacking Rifle Build (twist + 108 reports):
Rokslide – 6mm ARC Velocities (22" example, general reporting):
6mmBR.com – 6PPC Cartridge Guide (100/200 yd benchrest context):
GunsAndOutdoors.net – 6 ARC twist rate reports (7.5 / 7 discussion):
6 arc twist rate - Guns & Outdoors Forum
Rael, thanks for your input, I have reviewed the information and if the freebore is 0.089” that should be sufficient for 58-64gr bullets in a 1:12 twist
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The 6 ARC IS a really nice and versatile cartridge, especially using heavy for caliber bullets in the AR-15 platform. However, my competition advice is that you will either shoot a 6PPC or you will be beat by one. The delicate .0085” case neck thickness is part of its mystery. Chamber neck dimension is a matter of personal choice but my .262 neck has produced the best precision although it requires neck turning on nearly every reload. My criteria are that the bullets go through the same hole at 100 yards and I will take time to turn necks. The most critical aspect of the chamber is that the chamber runout is less than 0.0002” but I take time to make mine 0.0000” so that the bore’s bullet engraving is perfectly consistent all around the bullet.
For the 6PPC shooting a 68g flat based bullet (my favorite is the Barts Ultra), the barrel should be a 14 twist 22” target crowned barrel in a Heavy Varmint contour to make weight with minimal barrel flex. I’d suggest using Vitavori N133 powder with the case full (around 29.0g of powder). The 6PPC case won’t hold a dangerous load with that powder but I advise testing around that point. I also suggest testing seating depth once you find the optimum powder charge. Mine likes a 0.010” jump but many like 0.0 jump or even a 0.010 push into the bore. Every 0.003” of jump counts with this baby so testing is required. Get a cut rifled barrel from a premium barrel manufacturer like Krieger, Bartlein, Broughton, etc. and have the manufacturer or a precision gunsmith chamber, thread and crown. Few gunsmiths know all about precision rifle making but most barrel manufacturers have precision machines and machinists to do the work.
The action makes little difference as long as it is trued and properly bedded. I like to glue the action into the stock for a few 0.005”s in 5-shot group size.
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I originally asked this question because I had bought a 6 PPC rifle from a guy from another forum. I received the rifle today, it’s a Rem 700 6 PPC .262” neck with a 25” Kreiger barrel and I’m so happy the action is not glued in because if I don’t like how it shots I can easily swap barrels. And then I see your post… what a coincident. My intension was to swap the 6 PPC for the ARC or a 6mm-223 but after reading your post I’m now curious. So to get started I don’t have any 220 Russian brass, so I took a few pieces of Hornady 6.5 Grendel brass, necked them down to .257” then necked them down to .243” and pushed the shoulder back at the same time with a (borrowed) 6 PPC full length sizing die, then turned the necks to 0.008”. The custom made brass fits the chamber and the bolt closes with very little effort. What are your thoughts of the 6 PPC with a 0.270” neck?
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Krieger is a top choice for 6PPC 100 yard competition and the barrel may still be usable. My first step would be to clean the barrel good. Use SemiChrome solvent to eliminate any ceramic-like carbon ring that may exist in the first six inches ahead of the chamber. Test it and see if it shoots. If it doesn’t:
If the bore looks good, I’d cut the barrel to 22” and re-crown the barrel with a flat crown, or at least re-crown it. Make sure the face of the muzzle is perpendicular to the bore, not the external contour of the barrel. 22” is the optimal barrel length for 100-yard bench rest, minimizing barrel flex, while providing enough velocity to work well and still make weight. We use longer barrels on magnum powder charges and long-range shooting to get higher velocity in order to minimize the effect of gravity.
If you see burned bore ahead of the chamber, then cut 2” off the threaded end of the barrel and re-chamber. There is a pretty good probability that this will work OK. You can always get a new barrel and have Krieger or some other cut rifled barrel manufacturer cut, crown, chamber and thread the barrel to your action.
It is easy to re-barrel a glued in action with the right action wrench that inserts from the rear. I actually use a release agent on my action and glue it in with epoxy. Then I can pop it out with little effort if I need to.
Your technique for making 6PPC brass will work fine but I just fire-form 220 Russian casers for the same cost. I have customized a 6 ARC by pushing my chamber reamer in an extra .053". Then I necked 6.5 Grendel cases down to 6mm and fireformed them. In a bolt action they shoot about 100-150 fps faster than the straight ARC. It shoots well but I still use a 6 Dasher in competition for velocity to 600 and 1000 yards.
Finally, I would note that Rem 700 actions are fine for competition but they must be trued in order to be competitive. You can look at the rear of the bolt lugs to see if the bolt lugs are true. If they are, you will see even wear on the back side of both lugs. If the surfaces are even, there is a pretty good chance that it has already been trued. The most critical element in the receiver is the front face that must be perfectly aligned with the barrel shoulder. That has to be confirmed by a gunsmith by disassembling it and truing it up in a lathe. Personally, I’d check the rear of the lugs and go shoot it. If all the bullets go through the same hole at 100 yards, I would not take it to a gunsmith.
My thoughts on .270 neck… some like it some don’t. I shoot a turned 0.0085 neck thickness in a .262 chamber and it shoots in the .000s. I’ll turn necks every reloading if it keeps doing that. Some get that with a .270 neck, some don’t. I use what works but haven’t tried a .270 chamber. I’d suggest you try 0.0085 neck thickness in your .262.
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- I will look for the SemiChrome solvent to clean the barrel. I have thought about shortening the barrel to 22”. I was always told that the 11 degree crown was best for target/competition barrels. My action is not glued in and I don’t think I’ll be doing that. But I will check the bolt lugs to see if they are wearing evenly. As for my homemade 6 PPC brass I am turning the necks to 0.008” thickness. Am I understanding you correctly, in a previous post you stated, “my criteria are that the bullets go through the same hole at 100 yards and I will take time to turn necks”. Are you saying that if they don’t go through the same hole you will continue to turn the necks until they do?