6MM PRC
- Thread starter lancexxx
- Start date
I've just started playing with one. It's only an 18" barrel. I started out with RL23 and 90 TGK, didn't make enough pressure to expand the cases. Then went to H4350 and it was ok. With the short barrel I thought to try RL15.5 and that's where I'm at. I got the 87Vmax up to around 3450 but it was pretty hot and backed off a little. Ended up around 3415/10ES with great accuracy. I had two older barrels chopped off and re done. Looking back, I wish I had done one in a Creed just to compare. I kinda think I could get really close to the same velocity out of both cartridges but I won't know for awhile.
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That’s what I used.
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Lance,
I am currently chambering my 7th 6mm PRC. I have two reamers for it, one with a .060 FB and one with a .130.
We are running the 75 grain vmax, 85 grain makers, and the 70 grain nosler / sierra BK. By far and away the most versatile powder we have put in it has been the Hodgdon Superformace. Groups are under 3/8 when shot from bags with a 3" bag riding system. Some barrels are around 1/4 moa when shooters do their part. all are 9 to 10 twist barrels.
We have also tried H4350, N160, and N555 with various degrees of success and accuracy - YMFV. We went as fast as N550 but nothing faster.
With 24" barrels and the 85 grain makers, we are at 4,000 fps but its right on the verge of showing pressure. 70 grain class bullets are around 4,200
if you want to give me a call I can give you charge weights.
B23
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LOL only the verge of pressure huh?
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Yes, we aren't seeing pressure consistently. Certain rifle setups can't handle pressure nearly as well as others. Example: rem 700's are known to have a lower pressure threshold than a custom receiver.
Our loads were tested on a Borden, Impact, and Terminus. Up here in PA, in the winter, the environmental differences allow us to push faster, but we all know it's not best practice tuning a load in the winter for year round shooting. For the common shooter, I would recommend the hover around 3850 for year round use. That is still cookin for a 85/87 class bullet.
My whole reason for testing this so deeply was to find an adequate 6mm AI (75 grain vmax at 3850 fps) replacement as I am tired of forming brass from Lapua 8x57 brass. Sure the 6x284 is nice but I'm not a fan of the rebated rim. I played with the 6x55 swede a little but the PRC case was just easy mode.
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Greg, have you done anything with shorter barrels? Good call on the action/pressure deal too. I'm running a BAT Hammerhead on this deal. When I ran H4350 it was with 90TGK Sierras. I only got to 3200 before I started light ejector marks on virgin Lapua brass. Still no stiff bolt but in my opinion, if it's leaving marks on Lapua or Alpha brass, it's too hot. In the past I've always gotten better velocity out of slower burning powders even in short barrels and it surprised me that I was able to go another 200fps with the RL15.5 granted it was with a 87Vmax instead of the 90TGK. The 90's shot poorly so I didn't bother loading them again with the powder switch. The 87's are shooting right around 3/8" 3 shot groups at 100. Only group I shot at any distance was 500yd, was under 3.5" in a switchy crosswind. Only about 1.5" vertical. It's shooting plenty good for hunting coyotes. I'm really wanting a longer barrel now... but this 18" is handy and long enough with a 9" can hanging off it.
B23
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I completely agree that custom actions reveal or hide pressure different then factory actions. I always get higher velocities with a custom action versus any of my Rem700's in the exact same chambering but that doesn't mean high pressure doesn't exist because it does that's how you're getting those extreme velocities in that size case, but, good custom actions do a VERY good job, almost too good, at hiding conventional pressure signs but again just because we don't see those signs in the form of heavy bolt lift, clickers, ejector marks etc etc doesn't mean high or even extreme pressure in some cases doesn't exist.
I've had this conversation with different barrel manufactures that do pressure testing and they'll tell you they get results back on crazy high chamber pressures doing testing but it didn't show really any traditional pressure signs like mentioned above.
It's easy to get velocity drunk I'm as guilty as anyone, especially, when using custom actions and tough as hell brass but there's no magic or secret sauce with this stuff and you don't get 4000fps with a 85gr bullet in a case with only 66-68gr H20 and a 24in barrel without some very high pressures. Heck 3850 is even smoking fast in this size case with a 75grainer and a 24in barrel. I shoot 75 Vmax in my semi custom SA Rem 700 6-284 w/12tw 26in barrel and H4350. It's certainly not a max load but is up there on the upper end using H4350 and I'm at 3680. I use a lot of RL26, it is often a top velocity powder in these size cases, and I'm sure I could most likely and fairly easily get upwards of another 200fps working up a load with RL26 or even RL17 but it damn near cuts holes with the load I have and I don't really shoot this rifle much anymore so I've never pursued it.
Woollybugger
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Any issue with ball powders in Cold weather? I saw hang fires with staball6.5 in 22 GT and Creed in alpha small primer brass at 20f and below. A buddy is shooting the 105 in a 6 PRC at 3500 with N560.
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I fully agree. These pressure ring copper bullets allow for much higher pressures than the traditional bearing surfaces of conventional bullets. As I mentioned in the first post, your mileage may vary.
It's always tough to get into specifics with velocities and charge rates on a forum due to the fact you don't know who is reading it. Everyone should follow proper reloading methodologies first. One of the most important things many people over look on this is powder humidity levels. If your powder is dry dry dry, like 20% or less b/c you're in the north and it's blowing dry heat in your house all day long, that powder is going to be HOT and it will over pressure much much faster.
That said, if you're getting X speed with no bolt lift, no extractor or ejector swipe, and your primer pockets are holding up - send it !
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Magnum primers will help with this but yes, it's a known issue with ball powders
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Woollybugger
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Running 450’s didn’t help. R17, Varget and most any VV was fine. Probably a cold ND weather thing.
NEVER had, ANY "issues" with StaBall 65 and Large Primers ( CCI or Fed F-210-M's ), in 2 Rifles and I shoot sometimes with, a Foot of Snow on the ground and Temp's in the 15 to, 28 Degree, Range If, NOT much Wind !
If over 7 mph Wind and cold,.. I stay Home, Drink Coffee and BS on,.. Here !
If, you Live anywhere Between, the Cascades in Oregon to the Dakota's and above Northern Nevada,...
JUNK, the Small Primer Brass,.. IMO
And NO, I'm NOT going to, Argue "This Point', with anybody, so SAVE,..your thought's, guys !
Large standard Primers, Shoot "Fine", ( Bug Holes ) In All the Creedmoors, .243's, .22-250's,.. etc !
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Woollybugger
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No argument, Just don’t want to make LRP 22 GT brass.
The Bench rest guys really like, the Small Primers / Brass But out huntin', in the Bitter COLD,.. No, Thanks !
Everything I own Has, Large Primers,. except the Pistols and One,. .223 Rem / 5;56.
If you don't want to "Convert" to, the Lge Primer Brass, you'll Have to Live with, some "Dud's" ( Hang Fires ).
I've discussed this with, 4 or 5 guys Now, All getting,.. "Hang-Fires." ( Mostly with,.. Ball Powders ).
There have Been a Few, Lucky One's that, "Can" shoot, Ball Powders with, Small Magnum Primers and they LIKE to Argue, with Me,.. ( Got tired of, it )
You MIGHT try, Drilling Out, the Flash Holes a "Bit" but, I'm NOT sure of, the Dimensions needed but, you can research it,. ask, on Here ?
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