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7/6.5PRC Pressure and Velocity ammo test

So it should go without saying but I will say it anyways. Lot of powder variances, bullet lot variances from lot to lot and not to mention bullet diameters, primers, brass lot etc... all can change the pressure and velocities. Be careful with what you do! Don't forget.... temperature, humidity, pressure, altitude etc... can have an affect as well. This test was run in a lab in controlled conditions.

Not to mention that differences in chamber reamer spec's of what we used for the test/in our guns here and the pressure test barrel vs what you might have in your gun and as well as what your barrel measures for bore and groove dimensions vs what our test barrel was made to can make a difference as well.

Again I have to give a big thanks to Hornady and Joe and Jayden there for supplying the brass, bullets (166 and 190 ATIPS) and running the test! Thanks to Tommy at Sierra for supplying the 183SMK and 197SMK bullets for the test. Thanks to Ken at Capstone for supplying the Berger 180 Hybrids and the N555 powder used in the testing. The guys here at Bartlein for making the barrel and for Scotty here doing the chamber work and pressure port work etc.. in finishing the test barrel.

Max working pressure for the round is 65,000psi.

Twist does not effect pressure.

All pressure and velocity data is for 10 rounds fired for each load.

The p&v barrel measured 32" finish length.
Twist = 1-8.25
5R rifling
Bore size = .2773"
Groove size = .2843"
Headspace = go +.0002"

All of the ammo listed below has N555 powder. All ammo loaded with CCI#200 Primers. All brass was Hornady brass. All primer flash holes where checked for and or deburred.

All bullets where seated .020" off the lands of a brand new chamber. This was not a bullet test for accuracy. So no bullets/ammo had the bullets seated closer to the lands or further off the lands. No load tuning was done in anyway shape or form. In making this statement no bullet clearly out performed one over the other. All bullets shot very good. Noticed I listed the o.a.l. of my loaded rounds and not the base to ogive dimension. Some of my o.a.l. data I left at home. Let me update that information later today.

So for the 180gr class bullets.... I will say as you approach the 57.0gr powder charge... approach it with caution as you are going to be hitting that 65psi limit even possibly before depending on all the variables. There where no flat primer signs, hard extraction etc... At the top I put in bold letters... average pressure that's because that's the average. There are rounds fired with in a group that could be over the number listed for velocity and pressure was even slightly higher... so these numbers are an average. A good example is the 55.0 load for the 190ATIP. The average is 64829 but there where 3 rounds that went just past the 65k limit.

I'm still reviewing numbers and data and with more data to come for H4831sc, RL16 and H1000 powders. So check this post from time to time as I will be making updates as more information comes in and I'll try and keep my original post #1 going as I get more info.

I was having trouble with the layout on the post. So I saved it as a pdf. You have to click on the attachment. I'll clean it up more later.

Later, Frank
Bartlein Barrels

P.S. it should go without saying but I will say this... "Guys keep your comments civil and think before you type!" Everyone involved with getting this testing done did not receive any $ compensation in anyway shape or form. Everyone did this as a request/thought from me and we all did it to help the shooting community using this round and that there is no baseline/data for to go off of. I don't even want to know how much time and set up it took Hornady to run the test and compile the data and the cost involved with that.
 

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So it should go without saying but I will say it anyways. Lot of powder variances, bullet lot variances from lot to lot and not to mention bullet diameters, primers, brass lot etc... all can change the pressure and velocities. Be careful with what you do! Don't forget.... temperature, humidity, pressure, altitude etc... can have an affect as well. This test was run in a lab in controlled conditions.

Not to mention that differences in chamber reamer spec's of what we used for the test/in our guns here and the pressure test barrel vs what you might have in your gun and as well as what your barrel measures for bore and groove dimensions vs what our test barrel was made to can make a difference as well.

Again I have to give a big thanks to Hornady and Joe and Jayden there for supplying the brass, bullets (166 and 190 ATIPS) and running the test! Thanks to Tommy at Sierra for supplying the 183SMK and 197SMK bullets for the test. Thanks to Ken at Capstone for supplying the Berger 180 Hybrids and the N555 powder used in the testing. The guys here at Bartlein for making the barrel and for Scotty here doing the chamber work and pressure port work etc.. in finishing the test barrel.

Max working pressure for the round is 65,000psi.

Twist does not effect pressure.

All pressure and velocity data is for 10 rounds fired for each load.

The p&v barrel measured 32" finish length.
Twist = 1-8.25
5R rifling
Bore size = .2773"
Groove size = .2843"
Headspace = go +.0002"

All of the ammo listed below has N555 powder. All ammo loaded with CCI#200 Primers. All brass was Hornady brass. All primer flash holes where checked for and or deburred.

All bullets where seated .020" off the lands of a brand new chamber. This was not a bullet test for accuracy. So no bullets/ammo had the bullets seated closer to the lands or further off the lands. No load tuning was done in anyway shape or form. In making this statement no bullet clearly out performed one over the other. All bullets shot very good. Noticed I listed the o.a.l. of my loaded rounds and not the base to ogive dimension. Some of my o.a.l. data I left at home. Let me update that information later today.

So for the 180gr class bullets.... I will say as you approach the 57.0gr powder charge... approach it with caution as you are going to be hitting that 65psi limit even possibly before depending on all the variables. There where no flat primer signs, hard extraction etc... At the top I put in bold letters... average pressure that's because that's the average. There are rounds fired with in a group that could be over the number listed for velocity and pressure was even slightly higher... so these numbers are an average. A good example is the 55.0 load for the 190ATIP. The average is 64829 but there where 3 rounds that went just past the 65k limit.

I'm still reviewing numbers and data and with more data to come for H4831sc, RL16 and H1000 powders. So check this post from time to time as I will be making updates as more information comes in and I'll try and keep my original post #1 going as I get more info.

I was having trouble with the layout on the post. So I saved it as a pdf. You have to click on the attachment. I'll clean it up more later.

Later, Frank
Bartlein Barrels

P.S. it should go without saying but I will say this... "Guys keep your comments civil and think before you type!" Everyone involved with getting this testing done did not receive any $ compensation in anyway shape or form. Everyone did this as a request/thought from me and we all did it to help the shooting community using this round and that there is no baseline/data for to go off of. I don't even want to know how much time and set up it took Hornady to run the test and compile the data and the cost involved with that.
Please excuse my ignorance Frank this is a genuine question as I’m really new to this cartridge as well as pushing loads to their full potential. If I’m getting that velocity with roughly .7-.8 tenths of powder less with the 180 hybrids in the n555 do you think that pressure reflects directly to muzzle velocity or amount of powder in the case or neither or both? I know above 2970fps in my rifle things start getting a little toasty with 56.8gr and 57gr. Thanks!
 
Thank You very much Frank for doing this. I shoot the 180 Berger out of your barrels and have gotten the same velocities that they produced. This information helps a lot.
 
Please excuse my ignorance Frank this is a genuine question as I’m really new to this cartridge as well as pushing loads to their full potential. If I’m getting that velocity with roughly .7-.8 tenths of powder less with the 180 hybrids in the n555 do you think that pressure reflects directly to muzzle velocity or amount of powder in the case or neither or both? I know above 2970fps in my rifle things start getting a little toasty with 56.8gr and 57gr. Thanks!
Nope honest question and not a dumb one.

Here is what we don't know on your gun vs the test barrel or my gun etc...

What reamer spec is your chamber cut to? If you could send me a copy of the print I can take a look at it and see if it tells me anything.

Also what we don't know is what bore and groove spec is your barrel?

Not to mention lot of bullets and lot of powder etc.. that can cause variances.

So if your at 2970fps with a lesser powder charge... and if you try bumping it up to 56.8 or 57 and as you say things start getting toasty! LOL that was a good one! I'll say it's probably a combination of things that as a guess is making you generate a higher pressure earlier and given you the velocities your seeing already and when you try and go to 57gr.... your seeing pressure issues of some sort.

So I wouldn't go any further with what you have in loading and your set up.

Again like I said... with a 180gr weight bullet... 57.0gr is pretty much putting you at 65k and a tad over.

I'll send you a pm as well.

Later, Frank
 
Nope honest question and not a dumb one.

Here is what we don't know on your gun vs the test barrel or my gun etc...

What reamer spec is your chamber cut to? If you could send me a copy of the print I can take a look at it and see if it tells me anything.

Also what we don't know is what bore and groove spec is your barrel?

Not to mention lot of bullets and lot of powder etc.. that can cause variances.

So if your at 2970fps with a lesser powder charge... and if you try bumping it up to 56.8 or 57 and as you say things start getting toasty! LOL that was a good one! I'll say it's probably a combination of things that as a guess is making you generate a higher pressure earlier and given you the velocities your seeing already and when you try and go to 57gr.... your seeing pressure issues of some sort.

So I wouldn't go any further with what you have in loading and your set up.

Again like I said... with a 180gr weight bullet... 57.0gr is pretty much putting you at 65k and a tad over.

I'll send you a pm as well.

Later, Frank
Thanks for responding! I don’t have the print but Jay Christopherson spun it up for me if you’re familiar with his print? It is your 32” 1.250 5r 8.7 or 8.75 twist I believe. I’m also at 5000ft above sea level here in New Mexico with about 0% humidity lately so I think like you said it could be a combination of a lot of things. Bullet diameter, the lot of powder, and my elevation compared to others along with the reamer specs. I’m just curious is all, this thing definitely hammers in that range. I have not got to compare it to anybody else’s in my area but if I get that chance that might narrow part of it down.
 
No I don't have his reamer print.

Yes conditions and bullet diameter etc... all variables.

Our barrel... it's in that min spec range we run. I'll pretty much say your barrel to the test barrel it's within a .0001" or .0002" for sizes. The test barrel was smack dab in the middle at .2273" x .2843". If your barrel is right at .0000" spec. that could make the difference as well.
 
Once fired brass is slightly harder than virgin brass.
The transducer used is for a specific brand of brass and it needs to be new.
If you test with once fired, the pressure readings will come out lower than with new brass even if it's actually exactly the same.

Doing testing with fired brass can get you into the danger zone of pressure.
 
Once fired brass is slightly harder than virgin brass.
The transducer used is for a specific brand of brass and it needs to be new.
If you test with once fired, the pressure readings will come out lower than with new brass even if it's actually exactly the same.

Doing testing with fired brass can get you into the danger zone of pressure.
Also brass can vary lot to lot in hardness. That's why Hornady supplied the brass. So when I loaded up the ammo I needed to record the lot number the brass came out of as Hornady would have data for that given lot of brass for calibration purposes as well.

One less variable that could be taken into account.

I offered to supply Hornady or ADG brass I had (all new) but they needed the lot number of the brass.

Just like I supplied the lot number for the primers, powder, and bullets regardless of the maker of the bullets I supplied the lot numbers.
 
Frank from using only N555 this pretty well confirms my findings on where the ceiling seems
to be with the 180 Bergers. Ive changed my charge weight's some time ago, so as to not push it so hard.
 
@FrankG I really appreciate the stuff you share with us. I make cut rifle barrels for a small company and enjoy hearing about the testing you do. You can never have to much info.
 
No I don't have his reamer print.

Yes conditions and bullet diameter etc... all variables.

Our barrel... it's in that min spec range we run. I'll pretty much say your barrel to the test barrel it's within a .0001" or .0002" for sizes. The test barrel was smack dab in the middle at .2273" x .2843". If your barrel is right at .0000" spec. that could make the difference as well.
This is all great information and I believe like you said before this gives us a solid baseline now. We appreciate this info sir!
 

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