.28 Nosler Pressure
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Engineering101
Well-Known Member
GoneHuntingOutfitter
I've read info that appeared to be pretty authoritative indicating that if you change the humidity content of your powder you will change the burn rate of said powder. In the Winter many of us live in places that call for the use of a heating system in a house such as a forced air gas furnace. Running that will drop the humidity in a house substantially and if your powder is in the house it will be effected. A tight lid on a powder container will not prevent this from happening if the low humidity condition persists. I have noticed the effect you mention using both RL-33 and RL-26 and Retumbo and it was my conclusion that with the humidity at 30% as it is right now in my reloading room that was the cause. Powders are manufactured to have a humidity more like 50% if I am remembering that correctly but certainly higher than 30%. So - that is my guess. Winter hit, the heater came on and your powder dried out.
I've read info that appeared to be pretty authoritative indicating that if you change the humidity content of your powder you will change the burn rate of said powder. In the Winter many of us live in places that call for the use of a heating system in a house such as a forced air gas furnace. Running that will drop the humidity in a house substantially and if your powder is in the house it will be effected. A tight lid on a powder container will not prevent this from happening if the low humidity condition persists. I have noticed the effect you mention using both RL-33 and RL-26 and Retumbo and it was my conclusion that with the humidity at 30% as it is right now in my reloading room that was the cause. Powders are manufactured to have a humidity more like 50% if I am remembering that correctly but certainly higher than 30%. So - that is my guess. Winter hit, the heater came on and your powder dried out.
Gonehuntingoutfitters. Do you think the humidity is what was causing your pressure signs. I never thought about that. My heater could be causing this problem. My load was 88.3 grains. Reloader 33 CCI 250 primers 195 berger bullets oal 3.740. .020 from lands shot really good. Now I'm at 85 grains reloader 33. Everything else the same.
coyotezapper
Well-Known Member
Heater??
88.3 RL33 should have you around 3095 fps at 67K so it could be slightly over pressured at this charge depending on actual burn rate. 85 grains should not be over pressured.
Have you measured your fired cases for case head expansion?
Post pictures of perceived pressure signs if you can.
HellsCanyon
Well-Known Member
Tagging this thread. Curiosity is piqued....
Mike
Mike
eklarsen
Well-Known Member
Can you pop one of your cartridges and reweigh it? I would also recheck that OAL by remeasuring the chamber, it sounds like you have the tools to do so and it will rule out a simple error.
longgunshooter
Well-Known Member
Marking -
hnts4fun
Well-Known Member
Tagging in. Build in progress…
Frank in the Laurels
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Simple solution, cut back on your powder until your velocity matches what it should be, if 85 gets you the right velocity then use 85.... Velocity is directly related to pressure ! Why ruin your casings to get 100 fps more, doesn't make sense, no animal will ever know that it's missing..
Kmccord
Well-Known Member
I have a Custom made ACA 28 Nosler, it has a 26 #4 Brux barrel, I broke the barrel in as what was listed earlier in this thread. After break in I started working on a load with 195 Berger, what I found to be a pressure problem using RL33 and CCI 250, was at 86gr., Ejector marks showed up, 87gr produced flat primer with one pierced, 88gr caused primer nipples, the velocity at 88 was at 3250. I since found my sweet spot with my rifle at 84.3gr with a .020 jump no pressure signs and velocity avg is 3093. My elevation is 440ft and the outside temp at the time was 61. The three shot group at 200yds measured .525in. I don't see how, on this forum, another person was using same powder and primers at 88 grains with little pressure and 89 starting to see some good pressure.
I was out this weekend with my new 28 nosler doing some load testing with the 195's. Temp was 34f 65% humidity 2000ft elevation DA 1400. I started at 83gr of rl 33 and worked up to 88. What I found was at 84.5gr I seen slight ejector marks and velocity was 3020. Keeping a close eye on case expansion and bolt lift I continued with my load testing. I found that case expansion bolt lift and the ejector marks did not change at all out to 88gr with a velocity of 3190. My best groups were around 87 87.5 and 88 with a ladder test at 300yards with a 1" group. I have a 27 1/4" benchmark on a trued 700 with greyboe stock trigger tech trigger. Coal is 3.745" that's .015" jump. So I'm not sure what to take on the pressure signs. I'm not sure if it's because of the soft nosler brass giving the pressure signs at such a low powder charge and not making any difference as I climb 5 grains in charge. Any thoughts?
Kmccord
Well-Known Member
If I measure tip to cartridge base I come up with 3.55", if I measure with my Hornandy tool, I get 2.835" to ogive, it is .020 jump to lands. I have not tried moving closer to the lands yet or further, I ran out of RE33 when I finally found a load to get me at half MOA or less at 200yds. I have enough loaded right now with RE33 to test at 400 and 600 to see if my grouping stay consistent. When I do get some more powder I plan to tinker with the jump to see if it improves.
