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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 shape and length provides some added benefits over the 28 nosler imo. Speed wise it seems to me that it can easily match or beat 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
 

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.
     

    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
     

    clcustom1911

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    When you say "check the inside of the brass" what do you check it with? A dental pick of sorts? Can you describe what you are feeling for, please?

    Thank you.
     
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    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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    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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    clcustom1911

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    You need these fancy 7mm's
    IMG_20190505_1202339.jpg

    IMG_20190505_1202536.jpg

    IMG_20190505_1203256.jpg
     

    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
     
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    THEIS

    Hi, Sincerely
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  • Nov 27, 2017
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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
     

    flounderv2

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    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.
    The cases are close so do what you want. Fyi I'm getting faster speeds with much slower powders than what people are able to get with their 28s. What they are doing with H1k I'm able to accomplish with 8133 which is a tad slower than retumbo. When I run H1k, things get zippy in a heartbeat with case capacity to spare and no / low pressures.
     
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    flounderv2

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    @flounderv2 have you done any more testing with this lately?
    Appologies. Work travel and my match schedule has been hectic lately plus I dont get the notifications when their are replies in here. I'll be doing quite a bit with it this weekend. Right now im running 180sat 3150 using 8133 and is a real pussycat with zero pressure. Same load with H1k pushed them at 3255 and still no pressure. Bot loads have plenty of case capacity left to run them faster. I'll try and load up a few this weekend until I hit pressure and see. With what I've seen so far I'm guessing 8133/retumbo will run 180s at 3200 without much issue. H1K can probably get them to 3275 ish and if you went with a slightly faster powder you would be over 3300 pretty quickly
     

    flounderv2

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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.
    Theres something to be said about having the right amount of case capacity for the powders available. That and how the powder stack sits in the case make a difference.
     
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    Switchbarrel

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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 shape and length provides some added benefits over the 28 nosler imo. Speed wise it seems to me that it can easily match or beat 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.


    Not knocking your round at all, just sharing info based on your Nosler info.

    My 28 Nosler has a 30” barrel; 86 grains of RL33 pushes a 195 Berger @ 3220ish. Bolt still easy to lift, no flattened primer, etc. Haven’t run it any higher as I was only hoping for 3150-3180 with the 195’s. Have read N570 is even better, got 5# to try it out. I’m using a 1-8.5” twist Krieger.
     

    Painless300

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    What is the difference in the 7LRM and your 7 PRC?
    The 7LRM also uses the 375 as the parent case.
    Just asking.
     

    Painless300

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    factory/industry support for the parent case

    Guess I’m just wondering why you would try to develop another case that has already been developed and supported by Hornady.
    Not being critical just a question. I have a 7LRM and it performs extremely well even in shorter barrels (22”).
     

    b6graham

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    Guess I’m just wondering why you would try to develop another case that has already been developed and supported by Hornady.
    Not being critical just a question. I have a 7LRM and it performs extremely well even in shorter barrels (22”).
    more likely to see better brass with a 7/300 PRC considering factory ammo and .mil stuff
    if adg/rws/peterson come out with 300PRC brass. it will be wayyyy before 7LRM
     

    Piper907

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    Tag... Thanks for sharing. I am thinking about building another long range gun pretty soon and this looks like it could be just what I am looking for... now if someone would only make 300prc brass!!!
     

    flounderv2

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    It been performing really well. I have 400 ish rounds on this barrel and theres hardly any erosion in the throat. WAY LESS than what I would expect to see for burning this much powder. I attribute it to using a bit longer jump and slower powder. Im posting updates/pics on my facebook page if you want to follow as Im not on here much any more. The link for that is in some of the prior posts here. To answer some of the questions asked b6graham, hit the nail on the head. I didnt want a 7lrm due to being stuck with brass and dies from them. The PRC will have much broader support across the board so its a no brainer for me. Hornady brass is cheaper and I suspect Peterson, ADG, Alpha or Lapua wont be far behind in making 300 PRC brass.
    Switchbarrel, you have a 3" longer barrel than me and using a faster powder. Im basically using the slowest powder I can find short of 50BMG. and at 3150 mark on the low side. H1k is 3280 with 180s so if we assume our barrels are the same speed and 15-25fps gain per inch of barrel at 30" I would be ~3325 ish with 180s so probably 3250 or more with 195s. I have no experience with Rl33 but if I can find someone to give me a cup or so, I'd be more than happy to test for you. I also dont have 195s but may be work buying a box for comparison in speed drop comparisons between 180s and those using the same load just to have as a comparison.
     

    7mmSTW

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    In my opinion there are two 28NOS rounds, if your chamber has a factory length throat you are not getting the velocity range with the 195’s or any other long bullet. If you increase the freebore sojourn don’t stuff the bullet down in the case you can easily get the 3150 range without crazy pressures. Personally I think Nosler missed the boat with this, as is typical with all their rounds, they are designed to run light bullets fast.
     
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