What's interesting is Scott's loads with similar powder charge (it's really close but different) the pressure was 5k psi less vs my load in the test barrel. His velocities where down about 60fps as well but his barrel was 2" shorter. I asked him what primers he was using. Waiting for a response. I know he used ADG brass and it's a different lot of 190ATIP bullets and I'll guarantee a different lot of 4831sc powder. Just goes to show how making changes makes a big difference in what happens and how it effects pressures and velocities.
7/6.5PRC Pressure and Velocity ammo test
- Thread starter FrankG
- Start date
A very useful lesson. I was initially confused at the speeds some people quoted when I first got into fullbore rifles. Then I realised some were running 30" barrels, or were at altitude, or as this shows running well over pressure. A good reminder to work up loads and be careful where you get your data from.
This also may explain some of the excessive barrel wear you read about
This also may explain some of the excessive barrel wear you read about
I’m still waiting. I should have it anytime now. I talked to them like 2 or 3 weeks ago checking for an update.
They are thru some testing that needed to be done and he said he should wrap up this stuff here pretty soon. I’ll ping him tomorrow for a check in.
Don’t worry… as soon as I get it… I’ll update the thread.
The game plan is all priority stuff as of right now.... is taken care of... the game plan as of right now is to get back to testing the 7mm stuff this Friday. So keeping my fingers crossed.
Hot off the press.....They're running the last of the test ammo right now. I'll post updates as I get them. I just got this now.... once again when I get everything back I'll update the spreadsheet and post it for a final overall..... here is what I got on the first load of RL-16. He's hoping to have it all finished up today.
180 Berger, RL16, 53.00gr, Avg. velocity= 2899fps, SD=8, ES=25, avg. pressure = 62848psi
Later, Frank
180 Berger, RL16, 53.00gr, Avg. velocity= 2899fps, SD=8, ES=25, avg. pressure = 62848psi
Later, Frank
Here is the last of it.... that attachment is all up to date.
180 Berger RL16, 53.00gr, 2899fps, SD 8, ES 25, 62848psi
180 Berger RL16, 54.00gr, 2942fps, SD 7, ES 18, 66228psi This load exceeded the 65k psi. Highest pressure came in at 68040psi and the velocity on that round was 2952fps.
180 Berger N568, 57.50gr, 2678fps, SD 4, ES 14, 45809psi, too bad you can’t get more powder in the case with the N568. Seating the bullet was already compressing the powder. Maybe you could stuff 58.0gr and get 2700fps or so. 3rd smallest group fired if I recall correctly taking a quick peek back at the data.
180 Berger RL16, 53.00gr, 2899fps, SD 8, ES 25, 62848psi
180 Berger RL16, 54.00gr, 2942fps, SD 7, ES 18, 66228psi This load exceeded the 65k psi. Highest pressure came in at 68040psi and the velocity on that round was 2952fps.
180 Berger N568, 57.50gr, 2678fps, SD 4, ES 14, 45809psi, too bad you can’t get more powder in the case with the N568. Seating the bullet was already compressing the powder. Maybe you could stuff 58.0gr and get 2700fps or so. 3rd smallest group fired if I recall correctly taking a quick peek back at the data.
johnnyi
Gold $$ Contributor
Thanks for sharing all of this data. Curious if you have the reamer print for the chambering producing these pressures?
I want to point out something here.
The load that exceeded the 65ksi at 68,040 psi netted a whole 10fps velocity increase.
Think about that.
3,000 psi OVER maximum and it was a lousy 10fps.
When you start chasing velocity and your over maximum load gets you 30, 50 or 75 fps, where do you think you are in relation to 75-80,000 psi?
That was another reason for running this test… to show how much a small change can make and why I posted some of that info.
Shooters are worried about getting another 100fps out of their gun…. Guys… put another click on the scope and be safe about things.
I’ve posted it in other threads… I’ll update this thread tomorrow and post it here again.
Here ya go.... also you can see where my bullets referenced in a brand new unfired chambered barrel.
Keep in mind.... your barrels actual bore and groove sizes, bullet lot variances....even some makers vary in the same lot, in the same box (this can not just mean base to ogive/oal of the bullet you need to think of bullet diameter as well!) and if your reamer is slightly spec'd differently will all effect bullet seating depth and pressures and velocities.
I don't zero out my caliper when doing the base to ogive dimension for my bullets. Take my number and subtract 1" if you zero out your caliper. So for example on the 183SMK... take that B-O dimension shown as 3.384" and subtract 1" if you are zeroing out your caliper. That would give you 2.384".
Also keep in mind O.A.L. gauges vary a little bit from one to the next. I have a Stoney Point set that I purchased way before Hornady bought them out.
Once I use a given bullet to check seating depth... I use that bullet as a master and keep it in a box for that barrel/rifle etc... that way if I want to recheck the barrel at a later date... I'm using the same bullet I used when I started.
Later, Frank
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tvaught
Gold $$ Contributor
This has been excellent info! From the best barrels in the business.
Edit: I'm editing my post so the discussion around the reamer print and these pressures have these great pertinent nuggets from @FrankG orginal post in this thread for easy review as well.
"Twist does not effect pressure.
The p&v barrel measured 32" finish length.
Twist = 1-8.25
5R rifling
Bore size = .2773"
Groove size = .2843"
Headspace = go +.0002"
Edit: I'm editing my post so the discussion around the reamer print and these pressures have these great pertinent nuggets from @FrankG orginal post in this thread for easy review as well.
"Twist does not effect pressure.
The p&v barrel measured 32" finish length.
Twist = 1-8.25
5R rifling
Bore size = .2773"
Groove size = .2843"
Headspace = go +.0002"
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When you guys look at reamer drawings and regardless of who made the drawings... I'd ignore the notes on the far right side of the page.... where it shows a .276" bore and a .2756" pilot size..... I didn't spec that. Some of that info carry's over from other calibers and it doesn't always get updated.
johnnyi
Gold $$ Contributor
Super awesome info and details that you have shared! I was just curious to reference compared to spots that I began to feel pressure spots. Then I was seeing that you had data on the super long bullet info as well. That’s were I thought maybe the reamer was for the 180 or the big ones. Looks like more geared to the 180. Thanks for sharing !
Even the 190 ATIPS shot really great. With the N555 powder I think it was the most accurate or 2nd most accurate bullet shot with that powder. The base to ogive dimension between the 190, 180B and 183's are within say .030" give or take a little. Even the long 197SMK are within that range as well.
It's not a short action round with those overall lengths running at or close to the 3.200" o.a.l.
Thank you for this information Frank it is enlightening and very interesting.
I went back thru my head and if I had to put a cost on this to run this test.... just in components even though most of it was donated....
If I just figured in barrel cost, brass, bullets, powder, primers, fitting a pressure transducer to the barrel, the cal adapter etc...I'd say the cost would be about $3700 to $4000 to do this on the low end. Most likely it's more. I've heard cost numbers for transducers etc...but don't know it all down to the exact penny and I've never asked.
So again I have to give a big THANKS to all that helped... Hornady, Sierrra, Berger, VV powder and the guys here at the shop in doing this and pulling it all off. Not to mention time on the phone/emails with all the parties involved. With out all this help.... we wouldn't have this data to help the shooting community.
If I just figured in barrel cost, brass, bullets, powder, primers, fitting a pressure transducer to the barrel, the cal adapter etc...I'd say the cost would be about $3700 to $4000 to do this on the low end. Most likely it's more. I've heard cost numbers for transducers etc...but don't know it all down to the exact penny and I've never asked.
So again I have to give a big THANKS to all that helped... Hornady, Sierrra, Berger, VV powder and the guys here at the shop in doing this and pulling it all off. Not to mention time on the phone/emails with all the parties involved. With out all this help.... we wouldn't have this data to help the shooting community.
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