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300 PRC Load Development with 20N29

GunnyUSMC

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Minuteman
Nov 24, 2022
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I am building a new 300 PRC and most everything hard to come by including bullets, primers, and powder. I do load 50BMG and have about 12lbs of 20N29. While i know that 20N29 is perfect for the BMG, I also know that some use it for some other Magnum loads. I would like to know if anyone has considered working up a load using 20N29 for something like the 300PRC. I have a little N565 but that is not going to last long and have been trying to find some N568. H1000 and Reloader 29 are simply not available.

I am planning to push 230gr Berger Hybrids or larger if/when i can find them with Lapua brass.

My build is going to consist of a Defiant Machine RUKUS LA mated to a Bartlein 30" 9.25 to 9 gain twist.

Please let me know if this is within the realm of the possible.
 
I am building a new 300 PRC and most everything hard to come by including bullets, primers, and powder. I do load 50BMG and have about 12lbs of 20N29. While i know that 20N29 is perfect for the BMG, I also know that some use it for some other Magnum loads. I would like to know if anyone has considered working up a load using 20N29 for something like the 300PRC. I have a little N565 but that is not going to last long and have been trying to find some N568. H1000 and Reloader 29 are simply not available.

I am planning to push 230gr Berger Hybrids or larger if/when i can find them with Lapua brass.

My build is going to consist of a Defiant Machine RUKUS LA mated to a Bartlein 30" 9.25 to 9 gain twist.

Please let me know if this is within the realm of the possible.
Sorry to see no one responded to your inquiry which is why I am, even so I don't use the 300 PRC. I load for the 300 Win Mag. (long throat) and I have used N570 in that cartridge with good results with 175 LRX, 180 gr. CRX or with 195 gr. or heavier bullets. Case fill capacity when you have a long throat (and the magazine length to go with it, 3.850" in my case) in the 300 WM, the loads are almost the same as in the 300 PRC (I can get about 1 grain more in the 300 WM compared to the PRC in the 300 Win Mag. based on discussions I have had with friends whom load for both) but... I would not consider using 20N29 in the 300 WM long throat/300 PRC because I think the burn rate is too slow. I would not even consider using 20N41 (which is a bit faster) in 300 WM even so it is really cheap to buy right now at Midway. Vihtavuori does not offer load data for the 20N29 in 300 PRC, I suspect because it is too slow... N568 would also be a very good powder to use, I managed to get a hold of 2 LBS when it was first released but unable to get more in the past year. H-1000 can be had if you are patient and if you set up your alerts on all popular wholesale sites (check your email often, not just throughout the day but also early in the morning and late at night is when I had the best of luck), I have been able to procure about 20 LBS of H-1000 over the past 2 years. N565 has also come to be available a few times and comes back every few months or so, so if you use the same alert strategy, you should be able to get enough to develop most all of your loads with that powder on the 300 PRC, and get slightly higher velocities compared to H-1000. H4831sc may also be a good option for lighter bullets up to 210 Grains: it is going to be the most temperature stable powder and it is attainable right now + is super, super accurate at lower velocities (E.g.: 72.5 grains @ 2850 fps with 195 TMKs in the 300 WM long throat with 26" barrel which may exceed max load in 300 WM but the pressures in the long throat 300WM/300 PRC will be lower) 300 WM 26" barrel, so basically almost the same load in 300 PRC should work and with your 30" barrel, you will gain about another 160 fps over my 26" barrel. VV N570 will get you the highest speeds in 300 PRC with bullet weights 180 grains on up, you can find it from time to time... You may also try the New StaBall HD (8 lbs jugs were available yesterday), it should do well in 300 PRC but, because it is new... It may not be as good at the end of the day compared to the more established powders and because it is a ball powder, if you are going to run compressed loads with it, in my experience, ball powders, as soon as they get compressed your SDs and ESs start climbing drastically. So... if you buy that powder, make sure you have plenty of case volume so you don't compress your loads. Hope this helps you a bit...
 
I don't shoot 300 PRC or the big 50... But I just don't think 20N29 is going to give you satisfactory results. Nothing is stopping you from trying it, but you'll likely be in uncharted waters. Your main issue will be a safe starting load as I doubt you'll be able to pack enough in a 300 PRC case to be dangerous. I'm betting it just won't give good results at all.

N568, N570, LRT, Magnum, H1000, Retumbo, 7828SSC are probably going to suit you better.

There are a few recipes using US869 you could give a whirl... And it's in stock.

Sorry man. Not much help.

Mike
 
VV N570 will get you the highest speeds in 300 PRC with bullet weights 180 grains on up, you can find it from time to time... You may also try the New StaBall HD (8 lbs jugs were available yesterday), it should do well in 300 PRC but, because it is new... It may not be as good at the end of the day compared to the more established powders and because it is a ball powder, if you are going to run compressed loads with it, in my experience, ball powders, as soon as they get compressed your SDs and ESs start climbing drastically. So... if you buy that powder, make sure you have plenty of case volume so you don't compress your loads. Hope this helps you a bit...

I have been monitoring sites for N560, N565, N570. Had a brief opportunity for some N565 in 1lb increments. Bought 8 of them just so I have something but that was not cheap.

I have been monitoring all the others you mentioned with no luck.

I did see the StaBall is available in 8lb containers. Considering whether it is worth getting some.

The biggest challenge for me though is primers. I shoot 6.5 Creedmoor and use small rifle primers, which i have been able to get a decent supply of. I need large rifle primers for 300PRC and they are just no where to be found. I have been struggling with deciding just how much of the other components to invest in before confirming that i will actually be able to reload the 300PRC.


... But I just don't think 20N29 is going to give you satisfactory results. Nothing is stopping you from trying it, but you'll likely be in uncharted waters. Your main issue will be a safe starting load as I doubt you'll be able to pack enough in a 300 PRC case to be dangerous. I'm betting it just won't give good results at all.

N568, N570, LRT, Magnum, H1000, Retumbo, 7828SSC are probably going to suit you better.

There are a few recipes using US869 you could give a whirl... And it's in stock.

Thanks... if i can ever get some primers, i may try developing a load with the 20N29. That is not my preference either, just working on a backup plan.

just gotta get some primers... i have none.... uggggghhhh!!!
 
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I have been monitoring sites for N560, N565, N570. Had a brief opportunity for some N565 in 1lb increments. Bought 8 of them just so I have something but that was not cheap.

I have been monitoring all the others you mentioned with no luck.

I did see the StaBall is available in 8lb containers. Considering whether it is worth getting some.

The biggest challenge for me though is primers. I shoot 6.5 Creedmoor and use small rifle primers, which i have been able to get a decent supply of. I need large rifle primers for 300PRC and they are just no where to be found. I have been struggling with deciding just how much of the other components to invest in before confirming that i will actually be able to reload the 300PRC.




Thanks... if i can ever get some primers, i may try developing a load with the 20N29. That is not my preference either, just working on a backup plan.

just gotta get some primers... i have none.... uggggghhhh!!!

OK, so as a cheaper option you may want to try StaBall HD which has similar burn rate to Retumbo (the load data is in the Hodgdon 2023 annual manual), you can buy the powder directly from Hodgdon: https://shop.hodgdon.com/winchester-staball-hd/

Also for large rifle primers check out:

CCI Large Rifle 7.62mm NATO-Spec Military Primers #34 Box of 1000 https://www.targetsportsusa.com/cci...ary-primers-34-box-of-1000-cci2-p-113016.aspx

Those primers should work for most of your applications as Magnum primers are pretty much unattainable right now... This primer should get you going... I am pretty sure the NATO spec primers run a little hotter than your conventional large rifle primers.

Don't wait too long to make a decision both the powder and the primers will be gone quickly. Best of Luck! - Chris
 
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Also for large rifle primers check out:

CCI Large Rifle 7.62mm NATO-Spec Military Primers #34 Box of 1000 https://www.targetsportsusa.com/cci...ary-primers-34-box-of-1000-cci2-p-113016.aspx

Those primers should work for most of your applications as Magnum primers are pretty much unattainable right now... This primer should get you going... I am pretty sure the NATO spec primers run a little hotter than your conventional large rifle primers.

Don't wait too long to make a decision both the powder and the primers will be gone quickly. Best of Luck! - Chris

I jumped on it immediately and ordered a case...

Thanks Chris!