300 PRC load data

[DangerRanger]

I hear people talk about increased pressure with the ADG brass but I haven’t really seen what that means as far as how much less powder to use. I’m going to work up a load with some Berger 215’s, RL26, Fed 215m with ADG brass. I’m think 76-80gr in .5 increments. Seem reasonable?

I’m loading exactly that combo. I started at 75 but went just past 80 before seeing pressure with a brake. With my can I can see an ejector mark in the high end of that range.

I’m an idiot though so don’t listen to me

 

[B23]

Alex, have you played with any of the 230gr Sierra MK's in these big 30's and if so how did it go? They have a pretty health BC for a 230 gr bullet.

 

[Alex Wheeler]

@GlennK has shot them, I think @tom has too. I have never shot them.

 

[GlennK]

@GlennK has shot them, I think @tom has too. I have never shot them.

I like them. Shot them in the 300 norma improved and will again. The 8 twist barrel requirement seems fast but i am willing to give it a shot. Should have some data in the near future. They seem to handle high velocities over 3100 pretty well.

 

[tom]

I sorted some, they sorted REALLY good. I haven't shot any though...kind of a slacker this winter!

Tom

 

[1bamashooter]

I loaded some 212gr LRX bore riders with R26 but haven't had a chance to shoot them yet might try today.

 

[Bradly S.]

Alex,

Would you mind expounding a little on the ladders you did with each powder? For example what sort of patterns are you looking for when shooting a ladder at 600yrds? What pattern tells you that barrel does/doesn’t like a particular powder?

 

[Ledd Slinger]

So far the 300 PRC seems to be an over achiever. The others I have built have also been that way. I am a little surprised at the velocities you can get out of this case.

I’ve always said how efficient the design of that case is. Now you see I wasn’t BS’ing you! Lol.
Been shooting the 33 cal version of the 375R a long time. If you ever give the 33 version a try you’ll be just as amazed. Very fast speeds for the amount of powder being burned. Barrel life is excellent in the 33 cal version. I’m sure barrel life will be good in 30 cal as well.

 

[Ledd Slinger]

For anyone interested in the 33 cal version of the PRC/375 Ruger, the 250gr Bergers prefer mid burn rates. I get excellent speed and accuracy with good ladders using H4350 and RL16 which are basically identical burn rate. Slower powders like 7828, H1K, RL26, and even Retumbo work well for speed also but I seem to get better ladders, accuracy, and speed consistency with the mid burn rates. 33 cal on the PRC/375R case will easily push 250gr Bergers up to, and even slightly over, 3K fps in a 26” long barrel which is significantly faster than any 338 Lapua 250gr factory ammunition offerings of 2850-2900 fps.

 

[Ledd Slinger]

Alex, have you played with any of the 230gr Sierra MK's in these big 30's and if so how did it go? They have a pretty health BC for a 230 gr bullet.

I tested them quite a bit in a 300 NMI against the 230 Berger. The Sierras measure out very well and shoot good. But in extensive testing where I used everything identical on both bullets in a 1 in 8” twist barrel to ensure the Sierras had a fair chance, the Bergers exhibited consistently better accuracy in every single test. Sometimes only slightly better, sometimes significantly better, but always better. No matter how hard I tried to tune and tweak the Sierras, the 230 Berger always won out on accuracy with any of the same changes in seating depth, neck tension, primer changes, and powder charges that I made to the Sierra.

So from my personal experience with testing the 230 Sierra, I can’t recommend them over the 230 Berger.

 

[Alex Wheeler]

Shot 3 shot groups today around the low node and the high node at 600yds. The low node was actually shot in better conditions that the high node. Its quite obvious the high node has more potential. All 9 shots held 1.7" of vertical. With they snow, mirgae and 0 degree temps Im happy with that. I did keep the ammo in the truck, as Im not trying to tune it for 0 dergrees. Velocities were very close to what I was expecting so this barrel may be done speeding up. Im at just over 80 rounds so far. No pressure signs today.
I am going to move out to 1k now when conditions allow, I'll start on seating depth next.

 

[Alex Wheeler]

Alex,

Would you mind expounding a little on the ladders you did with each powder? For example what sort of patterns are you looking for when shooting a ladder at 600yrds? What pattern tells you that barrel does/doesn’t like a particular powder?

The 7828 would climb the target then drop down and start climbing again. The RL23 was too wide, it looked more round. They both had small looking "groups" in them but the overall pattern tells you it will not be repeatable. The H1000 ladder stayed narrow, climbed the paper and had distinct nodes. The mistake people make when reading a "ladder" is focusing on the good spot. You have to look at whats happening outside of that to know if its the right powder choice. The overall shape is showing you the harmonic pattern of the barrel, literaly how its vibrating. From my experience, a barrel/powder combo that creates a straight up and down vibration is desirable for accuracy and repeatability.
Its not from this rifle, I didnt bother saving those targets, but below is what I want to see. This was at 600 with a 300 NMI I had. It was the most accurate one I have ever seen. I want them to be narrow, climb straight up, no angle, width, or roundness. Sometimes you will see a good one but it goes wide in the node. Usually that can be cleaned up with seating or neck tension.

 

[Ledd Slinger]

Tall and narrow with single shot ladders is a good result when choosing a powder. For finer tuning, I have come to like ladder testing with 3 shot groups the best because it shows me group shapes. A good node to me will have nice groups with the same triangle shape laid over the top of each other.
Groups can be small in a ladder with the same general POI in a node but if one is a triangle shape, another horizontal, and another vertical, then I don’t fully trust it and will continue tuning.

That upper node on the PRC is starting to look good

 

[Alex Wheeler]

Yep thats how its done. Ladders are for roughing and picking components. Groups are for tuning.

 

[tom]

+- 3,000 with 230s on h1000? That's gonna be handy!

Tom

 

[WIB3]

Alex, have you tried MRP-2 yet.

 

[Alex Wheeler]

Nope, have not seen Norma powder in a long time. I shot MRP in a 260 ai about 10 years ago. Have you tried it?

 

[kev77]

I like them. Shot them in the 300 norma improved and will again. The 8 twist barrel requirement seems fast but i am willing to give it a shot. Should have some data in the near future. They seem to handle high velocities over 3100 pretty well.

I shoot the 230smk in my 300norma at 3100+ shoots very well in a 6g 8twist barrel. This was at 1500yds

 

[Alex Wheeler]

I shoot the 230smk in my 300norma at 3100+ shoots very well in a 6g 8twist barrel. This was at 1500yds

Are you pointing or trimming them? What kind of vertical will they hold on average at 1500+? Any vertical fliers?

 

[Alex Wheeler]

Ran the upper node at 1k at -9 this am. Forgot the ammo in my truck last night so I did my best to warm it up. When things get this cold they start to fight you a bit. ES was a little higher than it has been which I think accounted for the one dropped shot, mirage was pretty bad too so who knows. Even still it shot 2 groups in the 3s for vertical, one in the 1s, and one in the 5s. It seemed to run about 10 fps higher this time out. My aim dot is 4".