300 PRC update

Bandit320

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Some times...when you use an 8 twist...and you get more RPMs out of your bullets....the A-Tips like to explodicate.....Poof...and now they are gone. Also...my personal testing shows that the 250's aren't good for the 300PRC....You just can't push them fast enough to out do the 230's.

I take it you’ve seen the a-tips explode in flight. I have seen references here and other places on the net that Hornady says not to exceed 290,000 rpm. 2,900 FPS ,for example, using the 230s or 250s in larger 30 cal magnums would seem reasonable. This would be approx. 260,000. What velocity in the 30 cal a-tips have you seen these explosions? Thanks for the help.
 
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b2lee

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    I take it you’ve seen the a-tips explode in flight. I have seen references here and other places on the net that Hornady says not to exceed 290,000 rpm. 2,900 FPS ,for example, using the 230s or 250s in larger 30 cal magnums would seem reasonable. This would be approx. 260,000. What velocity in the 30 cal a-tips have you seen these explosions? Thanks for the help.

    To my knowledge...I personally have never had a 30cal A-Tip explode in my rifle.....maybe once when I had a fairly easy shot with a no call. However....I've seen a few 8 twist barrels pushing 2950+ and seen the *poof* at 15-30ft past the muzzle.

    Have you ever shot a bottle rocket up in the air...and it goes up...explodes and leaves that tiny little smoke signature?....that's what a few A-Tips I've see explode look like.
     
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    b2lee

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    Thanks for that info. That surprises me since Hornady recommends an 8.5 twis for the 250.

    Yes..but look at the speeds they recommend. SLOW....the 250 needs to be pushed fast for the BC to kick in....I've found much better luck with the 230's past 2000yards. So....if you push them fast twist slow MV....fine....if you push them fast MV and slow twist fine....but when you are me...heh...and you push them fast MV in a fast twist.... POOF! So...I stick with 9 twist...and I think I've proved a history of good luck with it.

    Today I'm testing a lighter bullet at more speed...we'll see how it goes....I'm just playing today....less about testing...and more about..."I just want to shoot".
     

    Bandit320

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    Thanks for lett me pick your brain. I had just ordered a Shilen Howa prefit from NSS last week and they offer 8 or 10 twist. They do offer a 4 grove “ratchet“ rifling that might be gentler on the jackets.
     
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    bunny too

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    Thanks for lett me pick your brain. I had just ordered a Shilen Howa prefit from NSS last week and they offer 8 or 10 twist. They do offer a 4 grove “ratchet“ rifling that might be gentler on the jackets.
    I pick @b2lee 's brain all the time, he is one of my best resources for the .300 PRC.
     
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    dwent

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    I've had quite a few issues come up with my 300PRC during load development. So starting out I had just under a 1 minute rifle which really pissed me off. Granted I was shooting factory ammo for the brass. So when I switched to load development I found my powder charges. I'm using H1000, RL26 and IMR7977. I'm down to a pound of RL26 now so am usingtheothers. I did my seating depth test. I was shooting at 200 yards and still couldn't get it to group worth a shit. If I was lucky to have a group under 1 minute. I tried multiple powders with multiple bullets and was racking up the round count with no answers. I've ran 220gr ELDX, 220gr MK's, 220gr scenars, 200gr ELDX and 225gr ELDM's. I was working with and talking to my smith during all of this and we were about to recrown or rechamber my barrel. I'm running a 28" 9 twist M24 SS proof barrel on an Archimedes action. I couldn't find anything wrong with the crown or chamber. I decided to try one more thing which was to pull the muzzle brake and see what it changed. I loaded up generic loads with.. 2x Hornady brass, 215m primers, 220gr ELDX with 0.020" jump pushed by 74.5gr RL26 and another with 220gr scenars 0.020" jump pushed by 74.5gr RL26.
    The 220gr ELDX with the brake shot about 1.5moa and without shot 0.750moa. The 220gr scenars shot right at 1 minute with the muzzle brake and shot about 0.500moa without. All shot data was taken at 200 yards. Another thing to note is I was getting single digit ES and SD's. The concentricity was checked,, bullets and cases were weight sorted for the above rounds. See attached pictures.
    220gr ELDX...edited from 225gr ELDM's
    View attachment 7631754
    220gr scenars
    View attachment 7631755
    I was surprised and relieved that I had found the issue. I purchased a Area 419 Sidewinder muzzle brake and I now have a shooter. My rifles only problem is now me. It shoots me 1/2moa consistently as long as I'm doing my part.
    Here is some load workup with H1000 and 225gr ELDM's now
    View attachment 7631757
    And with IMR7977 and 220gr scenars
    View attachment 7631758
    All data taken at 200 yards. That is the furthest distance I was able to shoot at the range. It sucks that I put almost 400 rounds on the barrel before I looked at some obvious things. Next time I will start going through the rifle a bit sooner and use this experience as a training tool.
    Here is the muzzle brake that I had on my rifle.
    View attachment 7631760
    And the one on it now during load development.
    View attachment 7631763

    Hope my post wasn't too long and helps someone else down the road. I've definitely learned a lot with my first build. Don't go cheap on anything!

    That is good info. Your issues sound a lot like the issues I have been having though I’m only just over 100 rounds in on this barrel it is still pissing me off.

    Im running a 24” proof carbon w/ PA Hypertap brake, in a bighorn Origin, mounted in an MPA BA ultralite. I’m having wandering groups and struggling to get under 1 MOA. I’ll get two in the same hole and then a flier 1.25” away. It is maddening.

    In the past week I’ve:
    -Bedded the scope base. Even though it was pinned it still needed it.
    -Skim bedded the V-blocks/tang in the MPA.
    -Lapped the seekins rings, which I was also surprised to discover that they needed lapping even after bedding the base.
    -decided to stop relying on the “wedge-lock” actions screws that come with the MPA and use loc-tite. The screws never seem to stay torqued.
    -swapped off my USO MR-10 for a Vortex AMG that finally arrived.

    I’ve been trying to develop a load with R25 and ELDX220s in Hornady brass. I finally got my Lapua brass and some H1000 in so I may restart the process with that if all of the above has no affect on grouping. But I will definitely be keeping the brake in mind now too.
     

    JBarton

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    That is good info. Your issues sound a lot like the issues I have been having though I’m only just over 100 rounds in on this barrel it is still pissing me off.

    Im running a 24” proof carbon w/ PA Hypertap brake, in a bighorn Origin, mounted in an MPA BA ultralite. I’m having wandering groups and struggling to get under 1 MOA. I’ll get two in the same hole and then a flier 1.25” away. It is maddening.

    In the past week I’ve:
    -Bedded the scope base. Even though it was pinned it still needed it.
    -Skim bedded the V-blocks/tang in the MPA.
    -Lapped the seekins rings, which I was also surprised to discover that they needed lapping even after bedding the base.
    -decided to stop relying on the “wedge-lock” actions screws that come with the MPA and use loc-tite. The screws never seem to stay torqued.
    -swapped off my USO MR-10 for a Vortex AMG that finally arrived.

    I’ve been trying to develop a load with R25 and ELDX220s in Hornady brass. I finally got my Lapua brass and some H1000 in so I may restart the process with that if all of the above has no affect on grouping. But I will definitely be keeping the brake in mind now too.
    My 300PRC doesn't like the 220gr ELDX. My 300WM with a 9 twist bartlein loves them. So far the lapua 220gr scenars and Hornady 225gr ELDM's shoot well now that I've fixed my issues.
    My 300PRC was all over the board before I found out what the problem was. I would get a few ok groups and then weird flyers. It was very frustrating. It sucks that I wasn't able to get it figured out sooner. Hind sight...I will always use a proven muzzle brake and will verify accuracy with and without the brake on.
    Let me know if it is the brake. I am curious to see if it mirrors my results.
    Jeremy
     
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    b2lee

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    Just for an FYI...I did some load testing today...barrel was already fouled when I ran this test group. Brass is virgin Lapua...so that may be a factor...and I could probably dial in the group with seating depth testing and/or barrel tuner...but the differences in MV with ES and SD are just too far out of line with what I want to do with them...which is 1k paper. They failed in that regard...but I'll post the pics for your entertainment.

    168gr Open Tip Match Bullets:

    168group_300PRC.png


    I could probably dial this group ^^^ in...a little shotgun-ish for me...the two in one hole looks good...but the horizontal is way out of line for me.

    168speed_300PRC.png



    ES of 32 is WAY WAY too much for me. I can dial my 245 EOL Bergers down below an ES of 10....but yea...this is virgin Lapua brass....I may revisit tomorrow when I go back and do some more testing of other components. But to see a MV of over 3500 fps.....makes you think...but nope...these won't be accurate enough for the purpose I need them for.
     
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    phlegethon

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    Just for an FYI...I did some load testing today...barrel was already fouled when I ran this test group. Brass is virgin Lapua...so that may be a factor...and I could probably dial in the group with seating depth testing and/or barrel tuner...but the differences in MV with ES and SD are just too far out of line with what I want to do with them...which is 1k paper. They failed in that regard...but I'll post the pics for your entertainment.

    168gr Open Tip Match Bullets:

    View attachment 7632495

    I could probably dial this group ^^^ in...a little shotgun-ish for me...the two in one hole looks good...but the horizontal is way out of line for me.

    View attachment 7632496


    ES of 32 is WAY WAY too much for me. I can dial my 245 EOL Bergers down below an ES of 10....but yea...this is virgin Lapua brass....I may revisit tomorrow when I go back and do some more testing of other components. But to see a MV of over 3500 fps.....makes you think...but nope...these won't be accurate enough for the purpose I need them for.
    The other thing is that they still get smoked on wind at 1k by the A-Tips.

    1621880236527.png
     

    b2lee

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    The other thing is that they still get smoked on wind at 1k by the A-Tips.

    Yea...with these...I would have to hit the big light switch on the right pole to turn the wind off....if it is a consistent wind...doesn't bother me too much. Tonight I'll load some just a bit longer...I was trying to match the boat tail with the neck/shoulder junction...and the bullet is just too short for that...so I'll do like maybe half the length of the neck....the powder fill was almost 95% at the seating depth I selected.

    I was getting about 2880fps out of the 250's today....was right at about 90F outside...brass looked good....but I'll stick with the 230's until my truck load of 245's come back in stock.
     

    dwent

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    Midsouth had 8# jugs of R26 in stock for a whole 45 seconds. Got an order in. We’ll see if it ships. It was out of stock before I could post it up here. Hopefully it’s a sign it will pop up at some other retailers soon.
     

    b2lee

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    Update from testing the 168 match bullets in the 300PRC. I added an entire grain of RL-26...and the speeds were much better on ES/SD...but just a tad faster....average was 3520fps. ES was 27 across 15 shots. This was on non-virgin Lapua.....groups were barely under and inch though....3 5shot groups...and they weren't very pretty.
     
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    Defender3

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    Midsouth had 8# jugs of R26 in stock for a whole 45 seconds. Got an order in. We’ll see if it ships. It was out of stock before I could post it up here. Hopefully it’s a sign it will pop up at some other retailers soon.
    It's been my experience with Midsouth that if your order is in, you will receive the item.
     
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    BCX

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    Update from testing the 168 match bullets in the 300PRC. I added an entire grain of RL-26...and the speeds were much better on ES/SD...but just a tad faster....average was 3520fps. ES was 27 across 15 shots. This was on non-virgin Lapua.....groups were barely under and inch though....3 5shot groups...and they weren't very pretty.
    Smokin,,,,,,, dam your SG must be up in the 3 plus range from that 1-9 twist?
     

    BCX

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    Just stay away from the Hornady ELD line and you should be safe, hahaha.
     

    BCX

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    How tight are the necks? Have 500 Lapua 300 PRC cases sitting in a unopened box. Haven't had a chance to inspect them yet.
     

    b2lee

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    How tight are the necks? Have 500 Lapua 300 PRC cases sitting in a unopened box. Haven't had a chance to inspect them yet.

    Well...I'd tell ya...but this is a family friendly site ;) REAL tight....like you better lube them...and mandrel them...and chamfer them with a VLD cutter...and they are still rather tight.
     
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    BCX

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    Perfect, should fire form that 40 degree shoulder nice and tight :LOL:
     

    Choid

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    Well...I'd tell ya...but this is a family friendly site ;) REAL tight....like you better lube them...and mandrel them...and chamfer them with a VLD cutter...and they are still rather tight.
    They are too tight. I loaded without doing anything to the necks, and to pull a few bullets from my ladder that would have been too hot, I had to whack the ram handle once I had the collet tightened to the bullet. Normally it is just an easy press.

    Overall pulled 219 215 Berger bullets today from ammo loaded for rifles I no longer have, so at least I should be good on my PRC and 300 Norma for a while.
     

    phlegethon

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    How tight are the necks? Have 500 Lapua 300 PRC cases sitting in a unopened box. Haven't had a chance to inspect them yet.
    They are OK after neck turning to 0.013 and a 0.307 mandrel.
     

    nealm66

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    Is there a guess as to how fast the 250 a tips can be pushed before any threat of failure in an 8 twist barrel? I have a couple hundred on the way
     

    phlegethon

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    Is there a guess as to how fast the 250 a tips can be pushed before any threat of failure in an 8 twist barrel? I have a couple hundred on the way
    I would say there is absolutely zero chance of blowing up an A-tip with a 300 PRC. You aren't going to get the velocity to do so.
     
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    Ledzep

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    Is there a guess as to how fast the 250 a tips can be pushed before any threat of failure in an 8 twist barrel? I have a couple hundred on the way

    I've shot them 2950ish in my 37" barrel just seeing how fast they'd go and no problems. It's a half-dozen of one, 6 of the other thing with the 230 vs. 250. Slightly better wind vs. less elevation. By 2000yd they're about the same thing.
     

    Bradv86

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    JBarton

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    "Estimated to ship in 1-4 months"
    Last time I ordered them I got them within a couple weeks. I feel it is better than nothing. I'm coming up empty handed and running low on components so if something pops up elsewhere I can always cancel the order.
     

    dwent

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    Last time I ordered them I got them within a couple weeks. I feel it is better than nothing. I'm coming up empty handed and running low on components so if something pops up elsewhere I can always cancel the order.

    My experience with them, at least as far as bullets goes, has been the opposite. I e had two different orders in for 212 and 220 ELDs since last year and every time the expected ship date comes up I get another email telling me it’s been pushed out. My 212s were “expected” yesterday. I’ll eat my words if they ship any time soon.
     
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    dwent

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    So after bedding my MPA and the scope base and lapping the rings, my groups definitely shrunk, and although they are not all that impressive I think if I can figure out where the vertical stringing is coming from this can be a .25” - .33” gun. I may need to mess around with the brake, as JBartons experience has indicated.

    In the photo with 6 groups, those are 2” dots. They are 1” in the other three.

    I’m shooting from a rest on an old rickety wooden spool, so that’s one of my problems I need to address. I’ll be shooting from an RRS ascend/anvil normally, but for load development I wanted free recoil. I was also racing the rain that day so I might have been subconsciously rushing the trigger too. First set of groups are what I was getting before bedding/lapping.

    Range is 100
    Load: ELD220 on 76.2 Gr. of R25 in Hornady brass with CCI #34 primers (all I have) bullets seated .002” from the lands.

    Rifle:
    MPA BA ultralite
    Bighorn Origin
    Proof Carbon prefit
    TT special
    PA hypertap brake
    Vortex AMG 6-24 in Seekins rings (picture is from another day)
     

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    themightytimmah

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    So after bedding my MPA and the scope base and lapping the rings, my groups definitely shrunk, and although they are not all that impressive I think if I can figure out where the vertical stringing is coming from this can be a .25” - .33” gun. I may need to mess around with the brake, as JBartons experience has indicated.

    In the photo with 6 groups, those are 2” dots. They are 1” in the other three.

    I’m shooting from a rest on an old rickety wooden spool, so that’s one of my problems I need to address. I’ll be shooting from an RRS ascend/anvil normally, but for load development I wanted free recoil. I was also racing the rain that day so I might have been subconsciously rushing the trigger too. First set of groups are what I was getting before bedding/lapping.

    Range is 100
    Load: ELD220 on 76.2 Gr. of R25 in Hornady brass with CCI #34 primers (all I have) bullets seated .002” from the lands.

    Rifle:
    MPA BA ultralite
    Bighorn Origin
    Proof Carbon prefit
    TT special
    PA hypertap brake
    Vortex AMG 6-24 in Seekins rings (picture is from another day)
    I really think the stringing is coming from the firing point. Looks pretty unstable, you might consider putting the rest on a prepared spot of ground or off the pickup bed and shooting prone?
     

    dwent

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    I really think the stringing is coming from the firing point. Looks pretty unstable, you might consider putting the rest on a prepared spot of ground or off the pickup bed and shooting prone?

    Yeah I’ve had that thought. Also considering bracing the spool up with 2x4s. It sits flat and solid but it’s so old that it is pretty rickety.
     

    b2lee

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    I'd say the stringing is coming from whatever that rest is....just throw an Atlas on the front and shoot. Always practice your groups exactly the way you intend to shoot for reals.
     

    b2lee

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    What bushing are you guys using for Lapua brass? Mine should be here this week!

    I'm using a .336 bushing with my Lapua brass.....un-turned necks...however....I'm only putting 10inch/lbs of force on seating....that may be too loose of a neck tension for most....I feel a .334 is a little tight at the moment....I don't have a .335. However, I'll probably end up turning necks...because I'm a nerd....so I'll have to revisit different bushings then.
     

    vergil

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    Hi guys, has anybody used standard large rifle primers instead of L.R. magnum primers in 300 PRC? Can't find any magnum primers in stock.
     

    Demonian

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    Hi guys, has anybody used standard large rifle primers instead of L.R. magnum primers in 300 PRC? Can't find any magnum primers in stock.
    Not with 300 PRC, however I have used them in 300 Win Mag with good results. I didn't see much velocity difference with them but I did see an SD/ES difference with the Magnum primers, so I ended up using the FGMM Magnum primers in my final load for that rifle. H1000 powder if it matters.
     
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    LongRangeAggie

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    Hi guys, has anybody used standard large rifle primers instead of L.R. magnum primers in 300 PRC? Can't find any magnum primers in stock.
    I've been using Federal 210M primers with no issues, @b2lee says that my SD/ES should come down with the 215M's so I'm on the lookout for some and will post results.
     
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    Rocketmandb

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    Hi guys, has anybody used standard large rifle primers instead of L.R. magnum primers in 300 PRC? Can't find any magnum primers in stock.

    I have used BR-2s since the get go. I did some testing with 215Ms vs BR2s and saw slightly higher ES/SDs with the 215s, so decided to stick with the BR2s. The key issue MAY BE in colder weather where the extra flash from the 215Ms will help ensure the powder fires evenly. For me, that's not an issue. I'm a little bit of a weather snob when it comes to shooting :)
     
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    Surly

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    I'm using a .336 bushing with my Lapua brass.....un-turned necks...however....I'm only putting 10inch/lbs of force on seating....that may be too loose of a neck tension for most....I feel a .334 is a little tight at the moment....I don't have a .335. However, I'll probably end up turning necks...because I'm a nerd....so I'll have to revisit different bushings then.
    I am currently running a Forster FL die with the .3085 expander ball (Hornady once fired, annealed, and chamfered with Henderson Trimmer) and am having issues with the seating pressure exceeding 100psi with Berger 245s. I am using the 21st Century Hydro press and with a wilson die. 21st Century is sending me a 200psi handle for the press. I have not tried the Lapua brass yet, but all this talk about tight necks has me curious. Shoot if I am already at this PSI with Hornady brass, I am only guessing it will be higher with the Lapua Brass. How are you only getting 10psi? I don't have all the measurements handy now, but with the .3085 expander ball and bullet diameter, I am at 1thou of neck tension.
     

    b2lee

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    expander ball or expander mandrel? And you mic'd it to make sure it is correct? 100PSI seating will give you some unwanted runout....and cause frustration. I can seat my bullets using a K&M arbor press with two fingers...and that throw lever is really short...no leverage at all.

    Hornady brass is soft...so you shouldn't have any problems if you annealed, mandreled and chamfered. spray some one shot down in the necks...and if you still get 100PSI...something is very very wrong.
     

    b2lee

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    Minuteman
  • Dec 30, 2018
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    N. KY
    Someone in Discord asked me to post a video of the AMP Mate running some 300PRC brass. Please forgive the shaky cam footage...I couldn't find my camera tripod. Just a quick short showing the function. Some say it is slightly pornographic in nature.