Frank are ya'll going to pressure test for normal barrel lengths,
like 24/26 or just go with 28/30/32 since that what guys are using in the field r/n?
- Thread starter Jackomason
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like 24/26 or just go with 28/30/32 since that what guys are using in the field r/n?
When the 7 PRC was a still a fetus (2018-2019 timeframe), Seth Swerczek had done a 7-6.5 PRC that he briefly used for hunting. I believe it was lovingly called the "7 doucher".
But yes, as far as real load data and serious testing, we haven't really done anything up 'til now with it.
Right now it’s just the 32” finish length. When the initial round of testing is done. The barrel will remain at Hornady. They can do with it what they will. My hope is that sometime… they will do more load development and put that data out there.
It would also be up to them if they like… they could cut the barrel down finish length wise to say 24” and run more tests etc…right now though again… 32” is where it starts.
Yes I did talk to Seth…. And I wasn’t even going to go there!When the 7 PRC was a still a fetus (2018-2019 timeframe), Seth Swerczek had done a 7-6.5 PRC that he briefly used for hunting. I believe it was lovingly called the "7 doucher".
I look forward to you guys doing this and getting some hard baseline data.
All of the ammo is shipping out today for pressure testing. Hopefully they can schedule the test in as quickly as they can time permitting.
There are loads with N555 powder, H4831sc and H4350. Bullets are 166 and 190 Atips, 180 Berger Hybrids, 183 and 197SMK and 180 ELDM's.
260 rounds in total for this round of testing.
Later, Frank
Bartlein Barrels
There are loads with N555 powder, H4831sc and H4350. Bullets are 166 and 190 Atips, 180 Berger Hybrids, 183 and 197SMK and 180 ELDM's.
260 rounds in total for this round of testing.
Later, Frank
Bartlein Barrels
What advantage does the 162 have over the berger 156? It's a few grains heavier but the 6.5 156 has a better BC.
If you have a 6.5 PRC built on a medium or long action then nothing.
I don't understand why a medium or long action makes a difference in this case. The 156 is longer than the 162, I understand that either one would need to be shortened to less than maximum length to fit in a SA mag. But if I'm going to expand a 6.5 PRC case to 7mm I would be looking to run a bullet in the 180 grain range in a medium action. I'd rather shoot the 156 over the 162 ELDM no matter what action I was using.
you are giving up a lot of case capacity running the 156 at short action mag length. The 162 being a bit shorter and generally running at a fast speed out of a .284 barrel compared to a 156 out of a .264 at similar pressures. Running a 6.5 PRC out of a long action can really wake it up.
I have to agree with what he is saying.
I go back to the 284win. It was originally designed to run thru a SA type gun but with heavier/longer bullets your stuffing them so far into the case your sucking up case capacity which in turn will make velocity suffer. If your going to seat heavier/longer bullets to use the case capacity you need to run the round thru a longer magazine box length / long action. Or like in F Class where the guns are primarily single shots so you don’t have this issue.
I feel the same way about the 6.5PRC and the 7/6.5PRC or similar type rounds. I feel they are better suited for a long action type gun or if you will a short action but a short action that has a slightly longer magazine box where the rounds can have the bullets seated out further. Kind of like the Defiance XM action which can handle up to a 3.250” length round vs a short action where typically the magazine length only can handle a 2.8” round or a smidge longer.
That's why my 6.5 PRC is on a tikka action. Just didn't see the point in the 7mm 162 over the 156 that works without having to expand the brass to 7mm for what I think isn't a better bullet. If you're going 7mm, I'm going to load 180's.
I’ve sold several rifles, to build one rifle with multiple barrels. To me it makes more sense than building several rifles at twice the cost. In my case it’s a 25 Creedmoor on a 737R that I plan on using for NRL Hunter. I’m trying to find the best hunting caliber that will fit in a short action. Looking at 7 SAUM, 7 Sherman Short, or 7-6.5 PRCW. I have a pile of 168 VLD’s that need used up. Everyone can talk about how great the 180’s are, and I agree they are, but 168 VLD’s have killed a lot of game and seem to fit best on a short action.
I just found this thread and very much appreciate Mr. Green working to get some pressure data
Short Answer: The 284 Winchester is a 56K psi cartridge (the 6.5-284 is 58K psi) and some shooters routinely push it above 65K where brass life is not good. The 6.5 PRC starts off as a 65k psi cartridge, so the brass is made to handle higher pressure.
For what it's worth, in a Hornady podcast, it was mentioned that several common competition 6.5-284 loads were pressure tested at above 65K psi. The 284 competition loads are likely not lower.
Longer Answer: By the early 1960's, Winchester wanted to compete against the Remington's Models 740 (semi-auto) and 760 (pump action) rifles which could chamber the 280 Rem, Remington's answer to the 270. Winchester responded with the Model 100 semi-auto and Model 88 lever-action rifles in 284 Win. Those rifles were originally designed around the shorter 308 Win cartridge. As is typical with those types of actions, the bolt strength is the weak link and they were designed to handle the loads of the 308. To get 270 or 280-like performance, Winchester got clever and developed the 284, which had a fatter case than the other two (0.500"vs 0.470" dia). They then rebated the rim to match the 308-sized case head. Bolt strength then became an issue. The backthrust against a bolt is related to max case (internal) cross-section area multiplied by the max chamber pressure. To match the bolt thrust of the more narrow 308 at 62Kpsi, the SAAMI Max Average Pressure for the 284 was limited to only 56,000psi. The later Norma 6.5-284 is only slightly higher at 58K psi.
Yes, it would be possible to make 284 brass that could handle higher pressures, but that would involve thickening web and the walls near the base. This would reduce case volume and velocity for those who don't need the extra strength. The 6.5 Grendel and 6mm ARC are in a similar predicament, BTW. The brass was thinned out to provide max powder capacity at the relatively low 52K psi needed to avoid bolt problems with AR15's. This, however has prevented its use at higher pressures in semi-autos with stronger bolts (bolt-actions with chambers that offer more support near the case head can go a bit higher, though).
For those who really want to stay with a 284 derivative and run higher pressures, there is a potential solution. The relatively new 6.5 and 338 Weatherby RPM cartridges use a longer variant of the 284 case that is beefed up to handle 65k psi. It would take cutting this brass down, forming and neck trimming, but the case life should be better. The propellant volume will be lower, though.
The question of "Why not the 284?" has come up several times in this thread. On one of his YouTube videos, Erik Cortina said that his 284 ( a Shehane, IIRC) was just as accurate as his 7PRCW. In fact, he said he carried the 284 to South Africa for a competition as a backup rifle. According to a couple of comments in videos, Cortina said that he switched to the "magnum cartridge", 7-6.5 PRCW to get better brass life. The history of the 284 Winchester is largely to blame for for this.
Short Answer: The 284 Winchester is a 56K psi cartridge (the 6.5-284 is 58K psi) and some shooters routinely push it above 65K where brass life is not good. The 6.5 PRC starts off as a 65k psi cartridge, so the brass is made to handle higher pressure.
For what it's worth, in a Hornady podcast, it was mentioned that several common competition 6.5-284 loads were pressure tested at above 65K psi. The 284 competition loads are likely not lower.
Longer Answer: By the early 1960's, Winchester wanted to compete against the Remington's Models 740 (semi-auto) and 760 (pump action) rifles which could chamber the 280 Rem, Remington's answer to the 270. Winchester responded with the Model 100 semi-auto and Model 88 lever-action rifles in 284 Win. Those rifles were originally designed around the shorter 308 Win cartridge. As is typical with those types of actions, the bolt strength is the weak link and they were designed to handle the loads of the 308. To get 270 or 280-like performance, Winchester got clever and developed the 284, which had a fatter case than the other two (0.500"vs 0.470" dia). They then rebated the rim to match the 308-sized case head. Bolt strength then became an issue. The backthrust against a bolt is related to max case (internal) cross-section area multiplied by the max chamber pressure. To match the bolt thrust of the more narrow 308 at 62Kpsi, the SAAMI Max Average Pressure for the 284 was limited to only 56,000psi. The later Norma 6.5-284 is only slightly higher at 58K psi.
Yes, it would be possible to make 284 brass that could handle higher pressures, but that would involve thickening web and the walls near the base. This would reduce case volume and velocity for those who don't need the extra strength. The 6.5 Grendel and 6mm ARC are in a similar predicament, BTW. The brass was thinned out to provide max powder capacity at the relatively low 52K psi needed to avoid bolt problems with AR15's. This, however has prevented its use at higher pressures in semi-autos with stronger bolts (bolt-actions with chambers that offer more support near the case head can go a bit higher, though).
For those who really want to stay with a 284 derivative and run higher pressures, there is a potential solution. The relatively new 6.5 and 338 Weatherby RPM cartridges use a longer variant of the 284 case that is beefed up to handle 65k psi. It would take cutting this brass down, forming and neck trimming, but the case life should be better. The propellant volume will be lower, though.
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I think a lot of this is driven by people are looking for the perfect short action magnum cartridge. The more time goes on it's looking like that is a fools errand.
With a bit of luck the XM action length will take of in popularity and if not become the new normal atleast become popular.
My dream rifle would be a switch barrel mid length action and be able to run 223, 6.5CM and 7mm magnum of some sort on the one rifle.
These already exists, they're called Tikka with a switchlug and different bolt stops
Just kidding, I was actually looking for a proper XM length Rem style action couple of years ago as a do it all switch barrel but the lack of magazines and stock/chassis options stopped me.
I did think about just doing it on a Tikka but you are limited in mag capacity and my thoughts are more comp rifle than hunting.These already exists, they're called Tikka with a switchlug and different bolt stops
Just kidding, I was actually looking for a proper XM length Rem style action couple of years ago as a do it all switch barrel but the lack of magazines and stock/chassis options stopped me.
There are a few places doing Tikka XM bottom metals and you can get XM mags in 308 and short mag, but nothing is 223.
Not sure why 223 is always such an issue. There are plenty of people running 80+gr bullets and have been for years, not sure why we are still stuck with 2.55" coal magazines.
I agree we need much better 223 mags especially for long coal. That’s why I went with 75 eldm and 80.5 Berger rather than 85/88 in my last 223 build because I didn’t want to modify mags.
I want to live long enough to see a AW style double stack double feed 20 rounds 223 mags with an adjustable latch
Im getting a 223AI done on a Tikka action and want to use CTR magazines that are too expensive to risk modifying.
Im going to try run 88s but may have to settle on 75/80s.
Until AI come out with a 223 I don't see 223 AW mags ever being a thing.
No reason the aftermarket couldn't do it but 223 never seems to get much love.
Everytime I think about doing the "ultimate multi cal" build I end up deciding it's not worth it/not practical yet.
Maybe the new XM action AI AT-XMC with changeable bolt faces is just around the corner....
