300 PRC update
- Thread starter DAVETOOLEY
- Start date
None at all. I was loading them one at a time which prompted me to check probably 1/3 of the casings as I ejected them. My new bottom metal that houses the 3.85" mags arrives tomorrow. Now it's load development time - though the Hornady load data makes it appear that RL 26 gives a wider spread of powder weight, so I'd like to try it first. But I can't find it anywhere. Unless Alliant miraculously ships a new run in the next day or two, I'll likely start with H1000 and see where it takes me.
That's kind of what I thought. Those two in the 2970s were so far out there that I'm wondering what was different. Since I haven't neck turned yet, I'm thinking that neck tension could be a culprit. I was struck by the number that fell in the high 2920s to mid 2930s. About 2/3 were in that range.
When I checked h2o capacity it was 11% over my 300 win brass. I don’t recall the exact numbers.
BIG CAVEAT ON WHAT I'M ABOUT TO SAY: I'm not using the most precise measuring equipment, but it's not bad either (RCBS analog ball micrometer).
I just pulled a random piece of new, untouched Hornady brass - literally, I reached into the box and just grabbed one. The neck thickness varied between roughly ,013 and .016.
I don't know what if any brass prep you did but one thing I always do with Hornady brass is straighten the necks and chamfer in and out. The way Hornady trims the brass to length it rolls out a lip on the case mouth. I've seen it cause a slight interference fit in some chambers. That could well be the reason for your two out liars. Neck tension alone would not cause that much increase in velocity. It's in our head that neck tension causes major issues but it's been my experience that it's over rated. The act of seating the bullet acts like an expander mandrel and pretty much makes all the neck tension the same. Brass hardness affects it more. That's why I don't anneal. They're all the same.
Can I use the Accuracy International Long Action AXAICS 338 CIP chassis and magazines for a Remington Long Action 300 PRC build? I would assume the longer 300 Win Mag CIP magazines would work in the chassis.
Hi Dave,
I did chamfer the necks. Could you expand on what you mean by "straightening the necks?" Are you referring to neck turning or something else? I will be neck turning next.
What did you use as a measuring device? Please don’t say a caliper.
Edit: I just ran some over a mandrel, inside/outside chamfer, calibrated my ball mic against a standard, and they were all .014-.015.
Last edited:
Run them over an expander ball or mandrel to straighten and uniform the shape then chamfer. A good chamfer on the OD to remove the lip.
Anyone possibly have 1x-fired or fire-formed brass who can send/sacrifice 6 samples to AMP so they can developed a AZTEC code (letter)?
Pilot is #31.
I only have new brass, but no rifle to fire-form any brass...not until May/June.
Thanks!
Pilot is #31.
I only have new brass, but no rifle to fire-form any brass...not until May/June.
Thanks!
If you find some brass, please let us know. I'm kicking myself for not ordering more when it first came out.
GunBroker. They have some right now in stock. If you don't have GunBroker, call the shop that's listing it for sale and buy direct.
I have a couple hundred pieces of Hornady 300 PRC - once fired a few days back.. also have about 100 loaded rounds.
If you have an interest pm me and I will get a count. All shot out of Barrett MRADs.
If you have an interest pm me and I will get a count. All shot out of Barrett MRADs.
I just want to verify I understand this question and response:
You can use the .338 CIP AX chassis with the .300WM CIP magazines for the .300PRC rounds?
I'm planing to build 300 PRC on Mausingfield action and carbon fiber proof barrel. I just don't know what chassis or stock to pick. Keep in mind it will be long range hunting sometimes target shooting, i want to keep rifle around 10 to 12 LBS i'm concerned about magazine length also loading 212 or 210gr bullets.
please help any advice is much appreciated. thank you
please help any advice is much appreciated. thank you
I'm not sure how the weight works for you, but the KRG Bravo doesn't seem too heavy and will take CIP mags. it's what I'll be putting my LRI Mausingfield Hunter 300PRC in when it arrives next week or so.
I have the SAAMI reamer as well as one with a shorter throat for reloaders.
i like the Fact that chassis is 3.8LBS and it will take long magazines. Thank you for Input.
First setback for me on my newly rechambered rifle:
I bought the Accurate Mag bottom metal and magazines to house the longer PRC round, but at the seating depth I'm currently using (puts overall length right at max of 3.7"), I am unable to chamber a round out of the magazine. Where the lips that hold the rounds in terminate, there is not enough room to allow the round to enter the chamber at a shallow enough angle - so it binds up. The only thing I can think of is to cut back the lips to allow the bullet to rise up enough early enough to guide the rest of the round in at a proper angle.
I bought the Accurate Mag bottom metal and magazines to house the longer PRC round, but at the seating depth I'm currently using (puts overall length right at max of 3.7"), I am unable to chamber a round out of the magazine. Where the lips that hold the rounds in terminate, there is not enough room to allow the round to enter the chamber at a shallow enough angle - so it binds up. The only thing I can think of is to cut back the lips to allow the bullet to rise up enough early enough to guide the rest of the round in at a proper angle.
Tweak/flair the front of the lips to give the round a more nose up orientation.
I think things are coming together nicely. I have brass on the way. Found some primers (CCI 250's) locally as well as H1000 and retumbo. I have Dies ordered but may have to go the Amazon route and then just return the unused dies back to amazon when they arrive. Dane @ DMR rifles spun me up a 29" tube for my DT. Only component limiting me at this point are the 225gr. pills. My brother has some 212 we can load for fun.
hopefully by friday of next week I will have something to post with pictures!
hopefully by friday of next week I will have something to post with pictures!
Will a Bighorn TL3 long action, feed from the 3.850 size bottom metal/magazines or will it need modification?
Thanks jwknutson17. Do you run the Accurate DBM on your rifles? I can't remember what you said pages back.
Cadex factory rifle for one with the 3.850 mag sleeve installed, and other is a Manners CIP mini chassis. My SAC built rifle that I haven't received yet will have a manners stock with Badger CIP bottom metal.
Last edited:
Cool. I didn't realize there were that many options for the CIP bottom metal for the 300s. One last question: what mags do you like for this cartridge.
I'm using accurate and MDT mags. I had a few of the MDTs that didn't seem to feed the best. I sent them back for replacement. Replacements look like the picture attached they have been working well. 3 out of the first 6 I ordered didn't have the MDT stamped on the back of the mag and had a different follower and lighter spring tension. The replacements all look like the ones in the photo and have been working flawless. I guess there was a slight difference in the stamp of the body and for whatever reason the newer ones work much better. The older ones would feed the first three rounds and not the last too. New ones work great. Same with the Accurate mags.
Attachments
Thank you again. I think I'm all set now to start collecting parts.
UPDATE:
I had been asked earlier whether I saw any signs of overpressure. I just found one casing where there is an extractor mark - I missed it when inspecting the casings pre-cleaning. I'm guessing it was one of those that jumped up ~40 fps. I found it because when I was priming, the primer didn't sit snug.
I've just cleaned, sized to 2 thousandths back, trimmed, and loaded 32 rounds. Why 32? Because I ran out of H1000, and my order to replenish is held up at the retailer for some reason. I found that Brownells has it, so I ordered a few pounds from them that will hopefully arrive this week. What is it with getting powder these days?
I also have 9 additional rounds that I also neck turned and annealed. I wanted 10, but one of those cases was the overpressure one - which of course I found after I'd neck turned and annealed.
I had planned to go to the range tomorrow to test better prepared brass vs my last numbers vs neck turned/annealed, but I might get rained out. As soon as I have more data, I'll post.
I had been asked earlier whether I saw any signs of overpressure. I just found one casing where there is an extractor mark - I missed it when inspecting the casings pre-cleaning. I'm guessing it was one of those that jumped up ~40 fps. I found it because when I was priming, the primer didn't sit snug.
I've just cleaned, sized to 2 thousandths back, trimmed, and loaded 32 rounds. Why 32? Because I ran out of H1000, and my order to replenish is held up at the retailer for some reason. I found that Brownells has it, so I ordered a few pounds from them that will hopefully arrive this week. What is it with getting powder these days?
I also have 9 additional rounds that I also neck turned and annealed. I wanted 10, but one of those cases was the overpressure one - which of course I found after I'd neck turned and annealed.
I had planned to go to the range tomorrow to test better prepared brass vs my last numbers vs neck turned/annealed, but I might get rained out. As soon as I have more data, I'll post.
I haven't begun load development yet as I want to get a good baseline of data. I'm using close to what the factory ammo load was purported to be. Mine is 78.5 gr of H1000 along with a 225 gr ELD-X. Primers are Federal 215M. My scale is an Ohaus that goes down to .02 gr accuracy, and I get all cases loaded with the scale showing 78.50 or 78.52, leaving me with a theoretical load ranging from 78.49 to 78.529 (or thereabouts).
As mentioned earlier, I REALLY want to try RL-26, but it is like a ghost at this point - I've heard stories, but can find no proof of its existence.
Well today I started my 300PRC journey by simply starting a spread sheet, laying out all the pieces I will need/want...and putting a price to it. Geez...this journey is going to be painful. Guess I better go work some more over time.
I was the same way. Luckily I was able to hide the cash for the barrel from my wife. Unfortunately I don't have enough hidden funds to get everything I need. So I will have to borrow my brother's magazine and bolt for my DT. Also his torque wrench.
Beats not having anything though
Similar threads
