7-300 PRC Initial Results - Winner

flounderv2

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I'll be doing most updates on my FB page so feel free to follow there but I've also copied all the initial data below.


Some of you may know that I had a reamer made to neck down the new 300PRC to 7mm to see what it would do. I.e. A 7-300prc . I got it back from Alamo Precision Rifles on Friday and was able to put about 30 rounds on it so far and the results are impressive. The case is minimally larger than the 28 nosler but the shape and length provides some added benefits imo. Speed wise it seems to me that it can easily crush the 28 nosler with less effort and lower pressure loads. The 28 nosler advertises it can run a 175 around 3125 and but I'm hearing guys say 195s at 3140-3150 with faster powders and in sure this is a warm if not hot load. I'm curently pushing 184 bergers at 3175 with a slow powder and zero pressure and the Barrel isnt even broken in yet. At these speeds it should already run a 195 at 3140-3150 and also no pressure.I played with it a bit over the weekend using retumbo and 8133 and with 82gn 8133 which is a slightly compressed load, Im at 3173 avg with an SD of 4.5 with 184 hybrid. Barrel is a 28" Hawk Hill Custom :) No pressure even with water test. For those that dont know, the water test is pouring water on the case to simulate shooting in rain and if you have a hot load you'll blow primers and get a locked up or hard to open bolt in a heartbeat. I had zero issues and it opened like a normal round. Retumbo is a bit faster still no pressure. This thing is stupid light recoil for the speeds. My original goal with this was to push a 180 pill at a mild 3100-3150 with a powder that gave me almost full case fill and no pressure and it seems to be working spot on for that. Ill post more as I keep testing. brass life test with the same load made it to 7 firings before I had indications of loose primer and thinning case web. I think with something like RL26 or H1000 you could probably push a 180 in the high 3200s to mid 3300s or a 195 around 3200 without being too hot of a load.

Update 1 - 7x firings with 81.4 of 8133 was averaging 3155 with the 184. Everything felt good until the last resize and primer went in pretty easy. Checked the case and saw the faint line of death around the base. Checked the inside and you can feel it getting thin. I wouldnt push it past 5 to be safe depending on your load.

Also realized the Hornady 300 PRC sizing dies are no good. They dont size far enough to the base at all even if you push a piece back to factory dimensions. Hornady you better check your PRC dies or you're going to have a lot of people pissed off they have a sticky bolt on any reloads because your dies arent sizing enough. They arent even changing the dimensions of the case anywhete close to the base from a fired piece to resized . I thought they were sizing way to easy for such a large case and now we know why. They need fixed ASAP.

Update 2 - Between the seating die being a bad design imo which also doesnt work with a Forester Co-AX without chopping down the seating stem, the fact that the sizer doesnt size properly or that the hole diameter for the bushing is massively oversized and causes crazy amounts of neck runout unless you teflon tape the bushing, I'm done with the Hornady "Match Grade" dies. Unfortunately they were the only ones making PRC dies when I needed to get them. I'll probably give them away at some point or maybe do something really silly with them out of frustration. I spoke to Dan Warner today at Warner Tool Company and I'm going to have him make me a set of custom dies. If you havent seen their custom dies, they truly are a work of art with no comparison. I've been considering a set of his dies for a while now and finally going to pull the trigger.
 
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doctordoctor

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I have not been able to test new brass yet in my 300 prc. I did reload 1x fired brass and had a sticky bolt every round. So now I wonder if it is a die issue! I was thinking brass. But I don't have any brass at the moment to test and I am in Hawaii
 

flounderv2

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I have not been able to test new brass yet in my 300 prc. I did reload 1x fired brass and had a sticky bolt every round. So now I wonder if it is a die issue! I was thinking brass. But I don't have any brass at the moment to test and I am in Hawaii
If you're using hornady dies my guess is they are the problem. The ones I have dont seem to size amywhere near enough
 

W54/XM-388

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Eventually you could wind up with like:

6.5 PRC
7/300 PRC
.300 PRC
338/300 PRC
Maybe even a 6.5/300 PRC

Pretty much a whole range of different possibilities.
 

Long Range 338

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Is Hornady the only source of brass for the 300PRC at the moment? 5 firings on low pressure loads doesn't seem that impressive to me. Another manufacturer producing better brass would probably give the 300PRC an edge in sales.
 

flounderv2

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Is Hornady the only source of brass for the 300PRC at the moment? 5 firings on low pressure loads doesn't seem that impressive to me. Another manufacturer producing better brass would probably give the 300PRC an edge in sales.
Yeah they are right now although I know others are considering. I'd like to see Peterson make some. Agree on 5 firings but it's a decent sized case and the dies are crap so theres a few different contributors.
 
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maverickasu

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@flounderv2 soo curious how numbers on this compare to Roberts 7mmAPR?

Wish I had seen this sooner I was in the shop about 515 today and woulda asked...
 

flounderv2

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@flounderv2 soo curious how numbers on this compare to Roberts 7mmAPR?

Wish I had seen this sooner I was in the shop about 515 today and woulda asked...
We havent had a ton of time to compare but I think he said hes running 180s at 3070 with 76gn. I forgot to ask what powder and if it was a hot load or not and dont know what the total case capacity is. Sorry I know that's not a good equal comparison or answer. I'm also still doing testing on the 7-300 prc so I'm not sure what it's full potential is just yet or what other challenges may he ahead. Its pretty early but I'm liking what I'm seeing so far.
 
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jasent

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You could use a 375 die with expander removed to bump shoulders and full case size. That’s what I use in my 338/375 ruger/prc
 

W54/XM-388

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6.5prc and 300prc are completely different cases. Common misconception
I had thought the 6.5 PRC was based off the same 375 ruger case (that the .300 PRC is) just shortened as well as necked down?
Is it based of a different case or completely new?
 

camotoe

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It's based on 300rcm. Has same 532 casehead as prc just for shortaction
 

Hairy Biker

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Much the same figures as the 7mm Boo Boo. I went the Warner die path and have not regretted it.
 

mactavish

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The case is minimally larger than the 28 nosler but the shape and length provides some added benefits imo.
I might be missing something, but SAAMI specs indicate the .300PRC is slightly smaller in every dimension than the 28 Nosler (except neck diameter, obvs). Given these deficits, how can any amount of shape variation in a 7PRC case (amounting to two thirds of very little, that I can see) amount to a "crushing" performance advantage in favour of a 7PRC? Also, what method of alchemy would allow this to be seemingly achieved with less effort and pressure?

Not having a pop or trying to be clever, just genuinely interested in what you think might be going on. My ELR 28 Nosler is still in build and I'm just gleaning info on people's experiences of choosing slightly different paths towards similar end goals, in the meantime.
 
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flounderv2

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I might be missing something, but SAAMI specs indicate the .300PRC is slightly smaller in every dimension than the 28 Nosler (except neck diameter, obvs). Given these deficits, how can any amount of shape variation in a 7PRC case (amounting to two thirds of very little, that I can see) amount to a "crushing" performance advantage in favour of a 7PRC? Also, what method of alchemy would allow this to be seemingly achieved with less effort and pressure?

Not having a pop or trying to be clever, just genuinely interested in what you think might be going on. My ELR 28 Nosler is still in build and I'm just gleaning info on people's experiences of choosing slightly different paths towards similar end goals, in the meantime.
I dont think you looked at the specs right. Case capacity is slightly larger on the 300prc and shorter oal case length as well. I can tell you it running very well right now. Had a 100lb girl shoot it this weeknd and she did it felt like a 6.5x47. I cold bored the 1 mile target with a second round followup with my (pussycat load) lol
 

flyer

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I would like to see someone try a 7-6.5 PRC, something a bit less overbore.
 

Milepost

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I dont think you looked at the specs right. Case capacity is slightly larger on the 300prc and shorter oal case length as well. I can tell you it running very well right now. Had a 100lb girl shoot it this weeknd and she did it felt like a 6.5x47. I cold bored the 1 mile target with a second round followup with my (pussycat load) lol
You need to look over the specs for each case again. The 28 Nosler has about 7-8% more case capacity over a 7-300 PRC. That equates to about 60-75fps faster for the 28 Nosler.
 

flyer

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Like a 7MM SS or a 7mm Saum?
The WSMs, SAUMs and wildcats seem to all be rare to the point that I worry about brass availability and it seems like there has been so much knowledge put in to recent "precision" cartridges that I would like to see something a bit more clean sheet.

I'm very tempted by straight .284 Winchester made from 6.5x284 Lapua Brass, then I thought how does 6.5 PRC compare to 6.5x284? Could 6.5 PRC be a good 7mm parent case without the rebated rim, a slightly shorter powder column and a bit more case capacity?

I think that would be easier to pull off than a Shehane.

If 6.5 PRC takes off and some very nice brass is made, it could be a nice round that doesn't need 80 grains of powder.
 

Milepost

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The WSMs, SAUMs and wildcats seem to all be rare to the point that I worry about brass availability and it seems like there has been so much knowledge put in to recent "precision" cartridges that I would like to see something a bit more clean sheet.

I'm very tempted by straight .284 Winchester made from 6.5x284 Lapua Brass, then I thought how does 6.5 PRC compare to 6.5x284? Could 6.5 PRC be a good 7mm parent case without the rebated rim, a slightly shorter powder column and a bit more case capacity?

I think that would be easier to pull off than a Shehane.

If 6.5 PRC takes off and some very nice brass is made, it could be a nice round that doesn't need 80 grains of powder.
I like the design of the 6.5 PRC cace too but with ADG making some high quality brass for the RUM and SAUM cartridges I don't think a 7-6.5 PRC version is needed. The 7 SAUM case only holds about 4 grains of powder more than a 6.5 PRC... And the 7 SAUM is well respected and used in the Benchrest community so it isn't going away any time soon.
 
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Edds

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........... the shape and length provides some added benefits imo. ......
What is it about the shape and length that provide benefits and what are those benefits?

I am working on a couple of Wildcat cartridges and I might want to utilize those features.
 

b6graham

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What is it about the shape and length that provide benefits and what are those benefits?

I am working on a couple of Wildcat cartridges and I might want to utilize those features.
ALCO's 168gr aluminum tip. .800 G1 BC, same as the 180 ELDM
 

THEIS

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ALCO's 168gr aluminum tip. .800 G1 BC, same as the 180 ELDM
Hi,

Now ONLY if those advertised BCs matched peoples field results you would never ever hear of another bullet manufacturer except Alco.....

AB got a 26% reduction in BC from the bullet they tested. Pretty much everyone I know of has gotten anywhere from a 22%-30% reduction in BC advertised on various Alco bullets.

Sincerely,
Theis
 

b6graham

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Hi,

Now ONLY if those advertised BCs matched peoples field results you would never ever hear of another bullet manufacturer except Alco.....

AB got a 26% reduction in BC from the bullet they tested. Pretty much everyone I know of has gotten anywhere from a 22%-30% reduction in BC advertised on various Alco bullets.

Sincerely,
Theis
lol