300-PRC ... sharing results (and a question)

[rustyinbend]

So I finally got some virgin brass (Lapua) for the 300-PRC barrel on my Barrett MRAD (Thank You Grafs). Thus far, I've been shooting factory Hornady 225-ELDM ammo and getting decent results, albeit with large ES's and SD's (expected from factory ammo) ... and then re-using that Hornady brass and getting lousy results. So yesterday I loaded two 10-round steps in my new Lapua brass with Berger 220's and Hornady 225's ... and got nice results and very tight groups even with the charge weight step-ups. The Bergers gave me a very nice node around 77.0-77.2 (2858 f/s) and the Hornady's gave me a flat spot at 76.2-76.4 (2808 f/s). Next activity is to use those two velocity nodes to load a 10-round group test for both, and see who gives the better groups. I feel like I'm the closest I've ever been to finding a solid reference load for my 300-PRC MRAD barrel, using supplies that I'm well-stocked with. Sharing just for fun ... but with one question: Do you guys think these velocities (2858) and/or 2808) are good for 300-PRC coming out of a 26-inch barrel? Just curious to get some opinions from other 300-PRC hand-loaders on whether I should stop here, or go higher in charge weight to look for a faster velocity node. That said, I'd be inclined to stop since the last couple of rounds were showing some just a hit of ejector prints and swipe marks, but no heavy bolt.

BTW ... I'm using Accurate MagPro powder and Federal Match Magnum LR Primers.

 

[Cascade Hemi]

So I finally got some virgin brass (Lapua) for the 300-PRC barrel on my Barrett MRAD (Thank You Grafs). Thus far, I've been shooting factory Hornady 225-ELDM ammo and getting decent results, albeit with large ES's and SD's (expected from factory ammo) ... and then re-using that Hornady brass and getting lousy results. So yesterday I loaded two 10-round steps in my new Lapua brass with Berger 220's and Hornady 225's ... and got nice results and very tight groups even with the charge weight step-ups. The Bergers gave me a very nice node around 77.0-77.2 (2858 f/s) and the Hornady's gave me a flat spot at 76.2-76.4 (2808 f/s). Next activity is to use those two velocity nodes to load a 10-round group test for both, and see who gives the better groups. I feel like I'm the closest I've ever been to finding a solid reference load for my 300-PRC MRAD barrel, using supplies that I'm well-stocked with. Sharing just for fun ... but with one question: Do you guys think these velocities (2858) and/or 2808) are good for 300-PRC coming out of a 26-inch barrel? Just curious to get some opinions from other 300-PRC hand-loaders on whether I should stop here, or go higher in charge weight to look for a faster velocity node. That said, I'd be inclined to stop since the last couple of rounds were showing some just a hit of ejector prints and swipe marks, but no heavy bolt.

BTW ... I'm using Accurate MagPro powder and Federal Match Magnum LR Primers.

View attachment 7718302
View attachment 7718303

Those are middle of the road loads and you have room to go up if necessary. I'd stop where you get the best ES/SD and tune with seating depth.

 

[rustyinbend]

Those are middle of the road loads and you have room to go up if necessary. I'd stop where you get the best ES/SD and tune with seating depth.

I always thought the sequence was to go "up" in charge weight until you see pressure signs (heavy bolt, ejector print, etc.), and then find the flat velocity node below that and load to test groups. It seems like going higher into heavier pressure signs might not be the best path. That said, I've loaded a ladder test with some Hodgdon Retumbo that I've recently acquired ... and see if that gets me to higher velocities without pressure signs. More work to do here ...

 

[Cascade Hemi]

I always thought the sequence was to go "up" in charge weight until you see pressure signs (heavy bolt, ejector print, etc.), and then find the flat velocity node below that and load to test groups. It seems like going higher into heavier pressure signs might not be the best path. That said, I've loaded a ladder test with some Hodgdon Retumbo that I've recently acquired ... and see if that gets me to higher velocities without pressure signs. More work to do here ...

I guess it depends on how much powder you want to burn and how bad you want to find pressure. I've found that "flat spots" in the single shot ladder are often statistical aberrations and you still end up doing a full work up regardless of the velocity clustering in the single shot pressure ladder. You have enough data to start your load development if that is what you want to do.

 

[Huskydriver]

I run 225 eldms at 76 retumbo and get closer to 2900fps fyi. Plenty fast for keeping that bullet super to past a mile.

Depends on what your goals are honestly.

 

[rustyinbend]

I guess it depends on how much powder you want to burn and how bad you want to find pressure. I've found that "flat spots" in the single shot ladder are often statistical aberrations and you still end up doing a full work up regardless of the velocity clustering in the single shot pressure ladder. You have enough data to start your load development if that is what you want to do.

That's kind of where I am. If any of these flat spots in the 2800+ velocity range show tight groups and single-digit SD's ... I'll declare victory and take that reference load to the next competition. I'm fortunate to have a bunch of supplies (powder, primers, cases and bullets) ... so that's not a constraint for me. I love the whole "testing and data analysis" part of load development. Frankly, the journey is more fun for me than the destination.

 

[rustyinbend]

I run 225 eldms at 76 retumbo and get closer to 2900fps fyi. Plenty fast for keeping that bullet super to past a mile.

Depends on what your goals are honestly.

Interesting ... I called Berger yesterday and for my setup (26" barrel, Berger 220 LRHT, Retumbo) ... they gave me a Start of 79.5gr, and a Max of 87.4gr. I've loaded a .2 ladder between 81.6 and 83.4 to end my test at the mid-point. Let's see where that gets me. My QuickLoad software says that 83.4 should give me a velocity of 2809. That said, I've found consistently that QL's velocity estimate can be low by as much as 100 f/s. Maybe I'll add a few cartridges to my test in the 79-80 range and start there. Need to ponder that before my next range trip on Thursday.

 

[Huskydriver]

I would love to see your case heads at anything above 80 gr of retumbo lol

 

[rustyinbend]

I would love to see your case heads at anything above 80 gr of retumbo lol

Check back late Thursday. I'll be happy to show you. If the first couple of rounds are ugly ... I'll just unload the rest and start over with lower charge weights.

 

[rustyinbend]

Holy Crap ... those were hot loads with Retumbo. I only got through 5 of the 10 ladder rounds before I stopped ... all with heavy bolts, big ejector marks, and cratered primers. Not sure where Berger got those charge weights, but they were huge ... average velocities of 3116 ... way to hot for me. I'm going to start the next ladder test in the 78-ish range and try again. @Huskydriver ... I was wr ... wro ... you were ri ... rig ... um ... I clearly need to make some changes for the next range visit.

 

[Huskydriver]

Holy Crap ... those were hot loads with Retumbo. I only got through 5 of the 10 ladder rounds before I stopped ... all with heavy bolts, big ejector marks, and cratered primers. Not sure where Berger got those charge weights, but they were huge ... average velocities of 3116 ... way to hot for me. I'm going to start the next ladder test in the 78-ish range and try again. @Huskydriver ... I was wr ... wro ... you were ri ... rig ... um ... I clearly need to make some changes for the next range visit.

lol well good on you for following up so others know.... I found the best accuracy with 225 eldms at 76 on the low end and 78 on the high end with lapua brass.

For all you aspiring new reloaders I was going to post this before but I figured I wasnt going to talk ole rusty out of his starting loads but just a friendly PSA......

Berger book loads for 300prc and 300 norma mag are stupid hot at the starting load just a big giant FYI so you dont destroy your brass thinking you are going to start middle of the road with berger load data for those two cartridges

 

[Cascade Hemi]

Interesting ... I called Berger yesterday and for my setup (26" barrel, Berger 220 LRHT, Retumbo) ... they gave me a Start of 79.5gr, and a Max of 87.4gr. I've loaded a .2 ladder between 81.6 and 83.4 to end my test at the mid-point. Let's see where that gets me. My QuickLoad software says that 83.4 should give me a velocity of 2809. That said, I've found consistently that QL's velocity estimate can be low by as much as 100 f/s. Maybe I'll add a few cartridges to my test in the 79-80 range and start there. Need to ponder that before my next range trip on Thursday.

I think you can estimate accurate pressure by just looking at velocity and the corresponding pressure while ignoring charge weight. My recommendation above was based on your measured velocities and I think it was fairly accurate.

 

[rustyinbend]

So guys ... here's what I got in my 76.2-to-78.0 Ladder Test. I started seeing very light pressure signs about halfway through. So if I loaded a group test at 76.8 and get tight groups, am I "done"? For 300-PRC, is close to 2900-ish for Velocity acceptable to shoot out to a mile or so? Any advice is appreciated. I'm just not sure what an acceptable velocity is for 300-PRC ...

 

[Cascade Hemi]

So guys ... here's what I got in my 76.2-to-78.0 Ladder Test. I started seeing very light pressure signs about halfway through. So if I loaded a group test at 76.8 and get tight groups, am I "done"? For 300-PRC, is close to 2900-ish for Velocity acceptable to shoot out to a mile or so? Any advice is appreciated. I'm just not sure what an acceptable velocity is for 300-PRC ...

View attachment 7721747

Well, you know the top and bottom of the pressure window. My humble advice is to start load development now. As always with hand loading, you're as done as you want to be.

 

[Huskydriver]

At 2900 fps a 225 eldm stays super until 2200 yards....... Think you are going to be good buddy

At 2800 it's like 2075 iirm

 

[rustyinbend]

Then that's the plan ... load to the charge weight just before the pressure signs, look for velocity in the high 2800's, with single-digit SD's and tight groups ... and then declare victory and go to the long-distance range to see if I can hit a mile target with my 300-PRC MRAD barrel. Thanks for the help guys. I've got great load data and terrific results with 300-WM and 6.5-CM, but this is my first time handloading 300-PRC.

 

[bunny too]

Have you thought about 230/250 gr A-Tips? I think you may be happier with them. What is your barrel twist? I am getting 2958 fps with 130 gr A-Tips with RL-26 (78.85gr a little warm.) Very happy with the load .37 MOA groups and reaches out a mile easy. Good luck, have fun and be safe (make sure you are wearing glasses with your test loads.)

 

[rustyinbend]

Have you thought about 230/250 gr A-Tips? I think you may be happier with them. What is your barrel twist? I am getting 2958 fps with 130 gr A-Tips with RL-26 (78.85gr a little warm.) Very happy with the load .37 MOA groups and reaches out a mile easy. Good luck, have fun and be safe (make sure you are wearing glasses with your test loads.)

I've got a bunch of Berger 220 LRHT projectiles, and a decent supply of Hornady 225 ELDM's ... but nothing in the 230-to-250 range. Twist is 1:8 ... with supplies so hard to find, I'll probably stick with the 220's for now, especially if they group tight and hit at a mile. And I ALWAYS wear eye protection, whether reloading or shooting. It's crazy not to.

 

[bunny too]

I've got a bunch of Berger 220 LRHT projectiles, and a decent supply of Hornady 225 ELDM's ... but nothing in the 230-to-250 range. Twist is 1:8 ... with supplies so hard to find, I'll probably stick with the 220's for now, especially if they group tight and hit at a mile. And I ALWAYS wear eye protection, whether reloading or shooting. It's crazy not to.

I apologize, I did not read read your bio Gunny, I would not have stresses the eye glasses. However 1 in 8 will have no problem stabilizing the 250's when you get the itch. Thank you for your service.

 

[rustyinbend]

I apologize, I did not read read your bio Gunny, I would not have stresses the eye glasses. However 1 in 8 will have no problem stabilizing the 250's when you get the itch. Thank you for your service.

No apology necessary ... it's a great reminder to everyone to always wear eye pro.

 

[tstanek]

Hi guys,
just want to ask. Since .300 200+ Gr Hybrids and ELD M´s are basically imposible to get (even asking dealers for ordering those wasn’t any kind of sucess) here in Czechia, I’m looking for some alternatives. I found 210 gr RDF’s in stock, but from what I’ve read and heard it seems it’s crap. Another option I came across were Scenar’s L 220 Gr. I have TMK’s 200 Gr, but I assume that’s too light for this cartridge. Local shop has 220 Gr TMK in stock, which seem last possibility I’ve found so far. The rifle is Bergara HMR 26 inch 1:9 , I have RL 25 and N555, which seem usable for this. But beside retumbo, rl 26 and h1000 there are another suitable powders available. Any ideas on this or experience with these bullets? Thanks in advance !
T

 

[Huskydriver]

Hi guys,
just want to ask. Since .300 200+ Gr Hybrids and ELD M´s are basically imposible to get (even asking dealers for ordering those wasn’t any kind of sucess) here in Czechia, I’m looking for some alternatives. I found 210 gr RDF’s in stock, but from what I’ve read and heard it seems it’s crap. Another option I came across were Scenar’s L 220 Gr. I have TMK’s 200 Gr, but I assume that’s too light for this cartridge. Local shop has 220 Gr TMK in stock, which seem last possibility I’ve found so far. The rifle is Bergara HMR 26 inch 1:9 , I have RL 25 and N555, which seem usable for this. But beside retumbo, rl 26 and h1000 there are another suitable powders available. Any ideas on this or experience with these bullets? Thanks in advance !
T

Never used the 220 tmk but I would imagine the 220 would do well out of your 1-9

 

[tstanek]

thanks for the input! Today I came across hybrids 200 Gr in our local store. Is it worth to try? I won’t be shooting ELR or so, 800-1000 yards max I expect.

 

[Max_The_Phoenix]

At 2900 fps a 225 eldm stays super until 2200 yards....... Think you are going to be good buddy

At 2800 it's like 2075 iirm

Hi
I know this thread is probably old but I though maybe I can get some help here

Loaded Some Virgin Lapua brass with Retumbo at 76grs at @20 thou off the lands. My tripod broke so I couldn't really get any velocity.
started with no ejector marks and crazy accuracy, I had one 3 shots group at 100 yards at 0.1 inches.
shot 43 rounds just to get the brass fireformed and do some practice, noticed the small smear mark from the ejector hole on the case head.

Action; Defiance Ruckus Tactical
Barrel: 28" Bartlein 5r HV 1:9
Lapua Brass
Hornady 225 ELDM
CCI 250

would love to see if anyone has some experience with this Brass, powder and bullet configuration.
Thanks

 

[mrcheesemoose]

Hi
I know this thread is probably old but I though maybe I can get some help here

Loaded Some Virgin Lapua brass with Retumbo at 76grs at @20 thou off the lands. My tripod broke so I couldn't really get any velocity.
started with no ejector marks and crazy accuracy, I had one 3 shots group at 100 yards at 0.1 inches.
shot 43 rounds just to get the brass fireformed and do some practice, noticed the small smear mark from the ejector hole on the case head.

Action; Defiance Ruckus Tactical
Barrel: 28" Bartlein 5r HV 1:9
Lapua Brass
Hornady 225 ELDM
CCI 250

would love to see if anyone has some experience with this Brass, powder and bullet configuration.
Thanks
View attachment 8218026

Curious but do you have pictures of the targets for the other 43 rounds? If r where they not this load?

 

[Max_The_Phoenix]

Curious but do you have pictures of the targets for the other 43 rounds? If r where they not this load?

Here is the picture
Some of the shots were used for sighting in the scope on a different target
My friend who is inexperienced shooter shot the first 2 columns on the leftbut anyway the worst group excluding flyers are around .7-.6 inches

 

[HemiPowrd]

Need some advice. I'm just starting load development for a new 300 PRC rifle. I just broke in the barrel yesterday with 60 rounds of Hornady 225 gr ELD-M which shot at an average of around 2900 FPS. I followed that up with 10 handloads of 230 gr A-tips in ADG brass over H-1000 at charges from 72.5 to 77.0 gr. 77.0 gr maxed out at 2837 FPS. All the brass looked pristine after firing. I'm thinking of loading 5 rounds each using 77.3, 77.6 and 77.9 and checking velocity and brass signs. Does that make sense? I'll be pretty happy if I can get close to 2900 with the A-tips. The intended use is to shoot long range out to 1700 - 2000 yards.

Rifle specs:
Action: ARC CDG
Barrel: Bartlein 1:9 twist 30"

 

[Max_The_Phoenix]

Need some advice. I'm just starting load development for a new 300 PRC rifle. I just broke in the barrel yesterday with 60 rounds of Hornady 225 gr ELD-M which shot at an average of around 2900 FPS. I followed that up with 10 handloads of 230 gr A-tips in ADG brass over H-1000 at charges from 72.5 to 77.0 gr. 77.0 gr maxed out at 2837 FPS. All the brass looked pristine after firing. I'm thinking of loading 5 rounds each using 77.3, 77.6 and 77.9 and checking velocity and brass signs. Does that make sense? I'll be pretty happy if I can get close to 2900 with the A-tips. The intended use is to shoot long range out to 1700 - 2000 yards.

Rifle specs:
Action: ARC CDG
Barrel: Bartlein 1:9 twist 30"

If you are doing the ladder test, you are doing it wrong
You need to find the flat velocity node in the ladder. Then take that load and adjust the seating depth. Remember when doing ladder test you need to make sure your brass preparation is almost perfect and all the bullets are seated at the same length, you need to take all the small variations out of the equation.
Don’t be chasing the velocity only, look for the accuracy. Even 2800 will stay super to those distances.
Good luck
Max

 

[HemiPowrd]

If you are doing the ladder test, you are doing it wrong
You need to find the flat velocity node in the ladder. Then take that load and adjust the seating depth. Remember when doing ladder test you need to make sure your brass preparation is almost perfect and all the bullets are seated at the same length, you need to take all the small variations out of the equation.
Don’t be chasing the velocity only, look for the accuracy. Even 2800 will stay super to those distances.
Good luck
Max

I should have mentioned I'm not doing a ladder test, just trying to reach a velocity at this point. I need to get my brass fire formed first so just looking at velocity for now. Once I find a velocity I'm happy with I'll see how it shoots and adjust seating depth accordingly. I also have a barrel tuner installed and that will be the final step to get the accuracy dialed in.

 

[HemiPowrd]

Made it out to the range today. Loaded up 40 rounds with 77.3 gr of H-1000. Loaded long and had to single feed each round.
Bartlein 30" 1:9 twist
Virgin ADG brass
Hornady 230 gr A-tip
77.3 gr H-1000
CCI 200 primers
COL 3.826"
Jump 0.015"

Barrel looks it was still speeding up with 110 rounds down the pipe. Getting around 2865 FPS now.

Barrel tuner test target. Looks like tuner in position 12 is dead nuts. Two shots at each dot.

 

[Rio Precision Gunworks]

Made it out to the range today. Loaded up 40 rounds with 77.3 gr of H-1000. Loaded long and had to single feed each round.
Bartlein 30" 1:9 twist
Virgin ADG brass
Hornady 230 gr A-tip
77.3 gr H-1000
CCI 200 primers
COL 3.826"
Jump 0.015"

Barrel looks it was still speeding up with 110 rounds down the pipe. Getting around 2865 FPS now.

Barrel tuner test target. Looks like tuner in position 12 is dead nuts. Two shots at each dot.
View attachment 8244792

I'd be cautious using this 2 shot test. Below I've taken all three groups labeled number 12 and put them on a single target.

If you take the aggregate dispersion, you'll find that tuner settings 0, 3, 9, 15, and 18 would all find themselves inside this aggregate group size.

 

[HemiPowrd]

I'd be cautious using this 2 shot test. Below I've taken all three groups labeled number 12 and put them on a single target.

If you take the aggregate dispersion, you'll find that tuner settings 0, 3, 9, 15, and 18 would all find themselves inside this aggregate group size.

View attachment 8244810

I used OnTarget to map the groups you specified. I do see your point and I will be doing multiple 5 shot groups to verify load and tuner settings. Below is what I came up with for the two composite groups per your suggestion.


Composite group with tuner set to 12:

Composite group using tuner settings 0, 3, 9, 15, 18:

 

[Rio Precision Gunworks]

I used OnTarget to map the groups you specified. I do see your point and I will be doing multiple 5 shot groups to verify load and tuner settings. Below is what I came up with for the two composite groups per your suggestion.


Composite group with tuner set to 12:
View attachment 8245067

Composite group using tuner settings 0, 3, 9, 15, 18:
View attachment 8245068

Awesome.

That will help you sort out the noise. Not knocking the tuner or anything else. Just easy to chase our tails if we don't look at big picture.