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300 PRC update

This thread kills me.

Origin long action inbound.

32" 1.25" straight blank sitting waiting for a sherman reamer

And those new new 208s and 220s with some RL33

Just need to decide on a chassis/stock (come on foundation release an 8 pound long action genesis 2)
 
Anyone try this?
20200211_180654.jpg
 
I've had a few that had very loose primer pockets...but no case separation. With a custom chambered Defiance Deviant and Bartlein barrel...I get zero growth to my brass after the first firing.

And if you look through the threads...I'm pushing some of these loads pretty dang hot.

I just had to scrap 25 h cases with 6x fired with 8 of them completely separated.
I don’t get it?
I did rum up bout 3000+FPS mv during load development.
Recommendations? Ideas? Is my chamber “clogged”and it’s building pressure?
 
I just had to scrap 25 h cases with 6x fired with 8 of them completely separated.
I don’t get it?
I did rum up bout 3000+FPS mv during load development.
Recommendations? Ideas? Is my chamber “clogged”and it’s building pressure?
I have a custom Curtis action and mpa barrel
 
What was powder used? How many grains and what bullet? There is a difference between 3000fps with N565 and H1000.

What was the growth of brass from second firing on? what was your trim length? What was bolt lift like? What kind of SD's and ES's were you getting?
 
What was powder used? How many grains and what bullet? There is a difference between 3000fps with N565 and H1000.

What was the growth of brass from second firing on? what was your trim length? What was bolt lift like? What kind of SD's and ES's were you getting?

H1000 Berger 215, 76.0-80.5 (throughout LD) I have to check notes on growth, trimmed to about 2.566, bolt lift has gotten (harder) SD from 20-7 ES bought the same (I’ll double check my notes tmw)
 
H1000 Berger 215, 76.0-80.5 (throughout LD) I have to check notes on growth, trimmed to about 2.566, bolt lift has gotten (harder) SD from 20-7 ES bought the same (I’ll double check my notes tmw)

At 80.5 grains with H1k is too hot with the 215s. Back it down a grain or more and you will be ok. I lost primer pockets after 3 firings at over 80 grains. If you want 3k, use RL26 or another powder like n565.
 
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Le Wilson has micrometer seaters in stock now for those who like to use an arbor press.

They appear to not be at The other stores (midway/brownells) yet so I’m going to risk it and wait to see if I can get a discount at those stores. They usually run 25$ more directly from Wilson it seems.
 
So while shooting my 300PRC suppressed off my tripod that uses an ARCA rail/clamp, I noticed several times the RRS ARCA clamp wasn’t providing enough clamping force to keep the arca rail from sliding back. Was thinking about installing an arca barricade stop to wedge the clamp. But truthfully I rarely shoot off a tripod. The ground was muddy yesterday so it called for it.

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arca lok

even with matching specs to RRS now it isnt perfect. go look at an MPA or MDT or JP chassis. not everything is kosher even when you have a lever over a knob
 
I just had to scrap 25 h cases with 6x fired with 8 of them completely separated.
I don’t get it?
I did rum up bout 3000+FPS mv during load development.
Recommendations? Ideas? Is my chamber “clogged”and it’s building pressure?
I've had some imminent separations but caught them before they split. Kind of special situation though as my first chamber was a touch out of spec. The brass never quite recovered. Had around a 30% loss rate at 4X if I remember right. Would be interested to see pictures. May help figure out what's happening.
 
I've had some imminent separations but caught them before they split. Kind of special situation though as my first chamber was a touch out of spec. The brass never quite recovered. Had around a 30% loss rate at 4X if I remember right. Would be interested to see pictures. May help figure out what's happening.
 
Thanks for your response

What are you using to measure your powder? Complete component list and your process? Verified powder weight on another scale? Who chambered your barrel? Heavy carbon ring in your barrel? Round count? Cleaning regiment?
 
Yea...what's up with the horizontal scuffing....powder is super dirty.....
 
The rings around the body are from poor chamber finish. The sooty neck/ shoulder looks strange. Doesn’t look like powder fouling at all. Has a lacquer like appearance.

Prw, head separations are not caused by excessive pressure. Excessive sizing causes that.

Like Jwknutson17 said, need details.
 
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That ol brass looks like the garbage brass I pick up after the communist rifles at the range
 
What are you using to measure your powder? Complete component list and your process? Verified powder weight on another scale? Who chambered your barrel? Heavy carbon ring in your barrel? Round count? Cleaning regiment?

Triple beam/digital. De prime anneal (torch) trim, tumble,resize. H1000 berger 215. .334 neck bushing. Barrel is damn clean. Got it from MPA. Less than 400 rounds. Clean it per mpa regiments
 
Triple beam/digital. De prime anneal (torch) trim, tumble,resize. H1000 berger 215. .334 neck bushing. Barrel is damn clean. Got it from MPA. Less than 400 rounds. Clean it per mpa regiments

I’ve been loading 76.5 an 76.0. I resize every time..?
 
Ok...so you deprime...then torch anneal before cleaning...hence the color of the necks....wait...you trim then resize?
 
Thinking about purchasing a 26” Proof Research SS 300PRC barrel TL3 LA prefit. Trying to see if they’ll do an 8.5 twist.

Anyone using their prefit barrels with any luck?
 
1. How exactly are you cleaning your brass (unit + media)? 2. What's your cartridge headspace measurement? 4. How many firings before the rings showed up?

Your annealing needs some work. You need more experience/consistency if you're gong to continue by hand and in all sincerity 300 PRC isn't a good annealing training round IMHO. Buy some Tempil paint or a stick at least then download a metronome app for your phone.

Those rings are no bueno, you need to eliminate all other potential causes and then send that back to MPA.
 
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@Prw , here is where I would start,
You may be sizing the brass too much.
.002 is plenty.
If that brass came out of my rifle I would send it back, it should not have those rings scored around it.
If you have a swithchlug on your mpa, make sure it is tight.
I think you may be over heating your brass, shouldnt be black.
Just my thoughts.......
 
1. How exactly are you cleaning your brass (unit + media)? 2. What's your cartridge headspace measurement? 4. How many firings before the rings showed up?

Your annealing needs some work. You need more experience/consistency if you're gong to continue by hand and in all sincerity 300 PRC isn't a good annealing training round IMHO. Buy some Tempil paint or a stick at least then download a metronome app for your phone.

Those rings are no bueno, you need to eliminate all other potential causes and then send that back to MPA.
Lol, sorry for the double post, great minds think alike?
 
I would be surprised if that chamber is correct.
 
I retired this brass. 7 or 8 reloads (cant remember) on this lot in one of my guns. 79.5gr of H1k. Full length size every time. Pockets went before any separation. This was the worst piece and there is barely any indication of separation. Just grabbed 10 pieces out of my recycling bin.
 

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Thinking about purchasing a 26” Proof Research SS 300PRC barrel TL3 LA prefit. Trying to see if they’ll do an 8.5 twist.

Anyone using their prefit barrels with any luck?

I would go for it. With the TL3 prefits I had (in 300WM) they all were excellent. Dont see why the PRC wouldnt hold up to Proof quality. Mine were carbon prefits but I hear their steel offerings are just as good. I wouldnt hesitate to use one.
 
My barrel is from MPA....my brass dont look like that...

I did have to throw out a batch from real loose pockets...but that was my fault....
77 grains of 4831 ?
 
I retired this brass. 7 or 8 reloads (cant remember) on this lot in one of my guns. 79.5gr of H1k. Full length size every time. Pockets went before any separation. This was the worst piece and there is barely any indication of separation. Just grabbed 10 pieces out of my recycling bin.

Ah their still good just throw a little locktite on the primers after you seat them.
 
Yeah, something is seriously wrong.
My brass looks almost new after firing even after 4+ reloads I could simply wipe some residue off the mouth and resize.



And what kind of lube are you using.
I think you see where I'm going. I've been lucky with chambers so no personal experience there till recent. However, I do reload several calibers and have some experience with bad/dirty dies, dirty brass, improper lube, bad depth (if you can think of something to screw up I've probably done it at some point) and depending on the press progressive or single can make things even worse. The scuff marks look like chatter to me, but to leave those kinds of marks during resizing it should have been pretty obvious. So, agreed it's likely the chamber but better to rule out other causes first. Hard to believe MPA let one out the door in that bad of condition.
 
Yeah, something is seriously wrong.
My brass looks almost new after firing even after 4+ reloads I could simply wipe some residue off the mouth and resize.



And what kind of lube are you using.


I’m bumping the should bout thousandths, using a forester co-ax, using imperial lube also a graphite for the necks,
 
I think you see where I'm going. I've been lucky with chambers so no personal experience there till recent. However, I do reload several calibers and have some experience with bad/dirty dies, dirty brass, improper lube, bad depth (if you can think of something to screw up I've probably done it at some point) and depending on the press progressive or single can make things even worse. The scuff marks look like chatter to me, but to leave those kinds of marks during resizing it should have been pretty obvious. So, agreed it's likely the chamber but better to rule out other causes first. Hard to believe MPA let one out the door in that bad of condition.

I bought a borescope, I have a slight carbon ring, I’m gunna clean an re check my reload process and keep y’all posted.
 
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Alas, the 245

 
Sitting here waiting on some ADG 300PRC brass to be released....

Did they say it was going to be released this year for sure? A friend who went to shot talked to them and heard otherwise. Second-hand info, so take it for what it's worth.
 
Did they say it was going to be released this year for sure? A friend who went to shot talked to them and heard otherwise. Second-hand info, so take it for what it's worth.
pretty sure it's like an any day now thing. same with the sherman brass