I do not yet have the file from the trace but did get to see it. It is very interesting. 49830 psi with 81.5 grains of rl33 2985fps. The trace is text book for a great trace but lower pressure than I would have thought considering how the brass is coming out. I tried bigger loads but didnt get much change in velocity. The trace clearly shows a lot of powder burning after bullet exit as well. Its a slow pressure peak indicating if I want more velocity i would need a quicker powder. I guess work harden the brass and anneal. Keep on shooting. Pressure is clearly safe. Sorry for the image its a text.
.28 Nosler Pressure
- Thread starter GoneHuntingOutfitter
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You really need some type of calibration ammo with pressure trace as slight changes with the sensor bonding, location, barrel dimension, and alloy itself can have an effect on reported pressures.
I do not use it for checking absolute max pressure but for changes barrel exit times and comparisons between different loads.
I do not use it for checking absolute max pressure but for changes barrel exit times and comparisons between different loads.
coyotezapper
Well-Known Member
I get around 62-63K pressure with 85 grains R33 and Berger 195 at around 3000 fps in multiple rifles measured with an Oehler 43 PBL which uses a strain gauge. My results almost exactly match Quickload once the powder burn rate is adjusted to the velocity and pressure measured.
With my current powder lot, adjusted burn rate with 81.5 grains R33 would be 52K
but at a much lower velocity than what you are seeing. I would believe VELOCITY first.
With my current powder lot, adjusted burn rate with 81.5 grains R33 would be 52K
but at a much lower velocity than what you are seeing. I would believe VELOCITY first.
I'm shooting 85gr of rl 33 out of a 28" 1:8 twist benchmark at 3110 velocity verified out to 1060 yards. I don't have all the fancy equipment to find pressures and all that but the brass is holding up ok. I think after 4 reloads they might be done. This rifle took 7 animals this year anywear from 550-900 yards and all one shot kills. I'm very happy with the cartridge. Only thing I'd like to see is lapua make some brass
Alex Wheeler
Well-Known Member
Things that can cause pressure issues or signs... chamber finish, hard carbon buildup, poor chamber job, Barrel dimensions, sharp ejector hole, untrued action. All these things can cause pressure signs. If you dont use jb or iosso to clean with from time to time you probably have some carbon build up. You cant dissolve hard carbon or brush it away. Chamber finish has a huge role in bolt thrust, a chamber thats not concentric to the bore will increase bullet engraving force and pressure, sharp ejector holes will show ejector swipes at low pressure, untrue actions will bind under pressure and cause heavy lift, and obviously bore dimensions play the biggest role.
coyotezapper
Well-Known Member
26" Bartlein 1-8" on all but one. The other was a Shilen 1-8"
coyotezapper
Well-Known Member
I don't have a baseline to compare my 28N brass because the rifles have all gone to new owners but my original 7STW brass from the original factory ammo ( there was no brass for handloading so I had to shoot factory ammo to get brass) lasted the life of the rifle - 1600ish rounds in my original R700 SS DM-B. I have had no issues with Nosler or Norma brass to date in any chambering. If I can't get Lapua brass I go Norma or Nosler as second choices.
coyotezapper
Well-Known Member
One thing to remember is max pressure is achieved in the first 2-3 inches of bullet travel so what AW is saying above is more than likely the culprit. After a good cleaning followed by a borescope inspection with the problem still occurring I would have the barrel set back slightly and rechambered.
I keep all of my overbore chamberings throats polished to help extend barrel life. Every 200ish rounds I polish with JB blue and finish with JB bright. This process seems to ****** the micro fracturing that takes place.
I keep all of my overbore chamberings throats polished to help extend barrel life. Every 200ish rounds I polish with JB blue and finish with JB bright. This process seems to ****** the micro fracturing that takes place.
I am also a user of JB blue with my cleanings. The rifle is true fired brass is concentric etc. After deer season is over here we will do more extensive testing. I shot a whitetail with it Saturday and again the bullet performance was amazing.
fishdundee
Active Member
I had this exact problem this spring with a Christensen ridgeline chambered in a 28n. I checked and tested everything I knew to do and as mentioned in the above comments with the only thing I didn't do was to try a different lot of brass. I believe the brass is the culprit.
revturbo9967
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old thread but i have had the same issues. pressure signs at 84.3 gr rl33 .020 off lands with 195 bergers, 27.5 1/8 barrel. they didnt seem to be there at the initial load development but now they are showing. im on the third reload of the brass, annealed the last time around.
kfreeze
Well-Known Member
How often do you clean the barrel? Everyone seems to like cleaning every 30 rds. The 28's seem to build up crud then lose accuracy and get pressure signs very fast.
