Pushing the speed limit! When do you back off? What pressure signs?

Palmetto-Pride

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    I am wanting to see how fast I can push my 6.5CM with Hornady 135gr A-Tips. I am up to 2840 FPS with 43.4grs of H4350 with zero pressure signs. I am going to load two rounds in .2gr increments until I start to see signs of pressure. I guess my question is at what signs do you put the brakes on and back off. Let me say I know different people tend to push the limit more than others and some people are ok pushing the boundaries a little further than others. I will admit I am the type that tends to push the limit a little, but also within reason (read not blowing myself or rifle up.....LOL) So what is your SOP when going for speed?
     
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    nikonNUT

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    Cratered primers (My big rifle does this regardless. Gotta bush that firing pin hole!), flattened primers, ejector swipe, extractor <whatever tis called when the case rim has a pulled looking mark>, bolt thru the head... I kid on that last one. Maybe...
     
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    boatsnstuff

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    What barrel length? Primers are a good way to gauge pressure but not always foolproof in my experience. Good article here - https://www.primalrights.com/library/articles/understanding-pressure.

    I tend to work up loads and look more for consistency than just velocity. If you want more out of the cartridge just get a bigger cartridge meant to go faster (6.5Creed —> 6.5PRC for example). In the end what you gain from pushing the cartridge is relatively minimal with respect to drop and wind drift. I’m always hesitant to be at the very top of safe pressure due to variables that can push you over the limit. Pierced primers are the point where I think it’s become unsafe and I’ve seen situations where one or two rounds pierce primers out of a box of 50 even if they were all supposedly the same load. Have fun experimenting, no “right” way - just what works for you.
     

    Rocketmandb

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    For whatever reason, on the rifles I have now, I get heavy bolt lift before any primer issues. On my last 300 PRC, I would get powder signs around the primers before anything else. On my old 6 CM, I had a bunch of primer issues.
     

    db2000

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    I use extractor mark. Can’t vouch for science behind it....but crescent circle seems mild to mod pressure and full circle is high pressure. Especially if it’s a bold full circle and not a faint mark.
    I’ve had a primer blow out before. 😳
     
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    Culpeper

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    And if you think modern published reloading data is lawyered up you are wrong. What happened was technology proved old methods resulted in overstated max loads. You can run hot, anneal all you want, but you may be pushing the limit to increase brass life while ignoring the other end of the case.


    The only good thing about OCW and other similar methods of load development is people are inadvertently picking a safer load under the pretense it is more accurate or precise. Not that there is anything wrong with that.

    On the other end of the spectrum if you have been following the .257 BlackJack Ace load maximums up to and including charts you will see people going too far to get to that point of precision or accuracy. There is something very wrong with this.

    If you are like me and find the first signs of max than back off .5 gr.and then rely on seating depth than there is a cost in shorter brass life. There are loose primer pockets and THEN there are loose primer pockets.

    If you are new to reloading just stay within the published data and don't fuck around with the brass other than fundamental sizing, trimming and so forth.
     
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    47guy

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    the question is why do you want or need to run it faster? run the numbers on a ballistic program that velocity gain does not make some huge difference in wind or elevation...add 60fps and see what you come up with then ask yourself is it worth beating the shit outta my gun and components.
     

    Palmetto-Pride

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    And if you think modern published reloading data is lawyered up you are wrong. What happened was technology proved old methods resulted in overstated max loads. You can run hot, anneal all you want, but you may be pushing the limit to increase brass life while ignoring the other end of the case.


    The only good thing about OCW and other similar methods of load development is people are inadvertently picking a safer load under the pretense it is more accurate or precise. Not that there is anything wrong with that.

    On the other end of the spectrum if you have been following the .257 BlackJack Ace load maximums up to and including charts you will see people going too far to get to that point of precision or accuracy. There is something very wrong with this.

    If you are like me and find the first signs of max than back off .5 gr.and then rely on seating depth than there is a cost in shorter brass life. There are loose primer pockets and THEN there are loose primer pockets.

    If you are new to reloading just stay within the published data and don't fuck around with the brass other than fundamental sizing, trimming and so forth.

    the question is why do you want or need to run it faster? run the numbers on a ballistic program that velocity gain does not make some huge difference in wind or elevation...add 60fps and see what you come up with then ask yourself is it worth beating the shit outta my gun and components.

    On a scale of 1-5 on reloading experience (1=New 5=Expert) I would say I am a 2.5 I have been reloading for rifle about 3-4yrs I haven't ever strayed to far from published MAX. Just wanting to see how fast I can safely push my 6.5CM I guess am trying to see if I can reach 6.5PRC speeds in a 6.5CM case for no other reason than "just because". The two rounds below the one on the left was 41.6gr of H4350 the one on the right was 43.4gr of H4350 running 2840FPS that is .5gr over Hornady's max and .2 gr over Hodgdon's max with no signs of pressure to me on the case. So for the hell of it I figured lets see how fast we can get her up to.
     

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    Culpeper

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    On a scale of 1-5 on reloading experince (1=New 5=Expert) I would say I am a 2.5 I have been reloading for rifle about 3-4yrs I haven't ever strayed to far from published MAX. Just wanting to see how fast I can safely push my 6.5CM

    Get yourself a primer pocket gauge if you are comfortable shooting just above max. If you want to see your max than you work up something like this but listen to exactly why he is doing this in the first place at the very beginning of the video where he discussed published load data and your own components.

     
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    Milo 2.5

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    I am with 47guy here, what are the gains, or are they worth it. Always bigger cases. Trust me, I have stepped on a few cases in my day.
    Today for me, it depends on if I want my brass to last for the barrel life. I do this, with new brass, I load charges to chrono, and see if velocity nodes are present, and try to have an idea where I may run into pressure.
    After I have ran this test, I start decapping primers with a universal decap die, going slow and feeling for resistance popping primers out. When they no longer pop out, just push out, at this point you are expanding case heads and your brass will not last long.
    I am no brass life fanatic, but brass needs to last the barrel life, or if you put a fair share of brass in service, it needs to last for 2 barrels, here anyway.
     
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    47guy

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    On a scale of 1-5 on reloading experience (1=New 5=Expert) I would say I am a 2.5 I have been reloading for rifle about 3-4yrs I haven't ever strayed to far from published MAX. Just wanting to see how fast I can safely push my 6.5CM I guess am trying to see if I can reach 6.5PRC speeds in a 6.5CM case for no other reason than "just because". The two rounds below the one on the left was 41.6gr of H4350 the one on the right was 43.4gr of H4350 running 2840FPS that is .5gr over Hornady's max and .2 gr over Hodgdon's max with no signs of pressure to me on the case. So for the hell of it I figured lets see how fast we can get her up to.

    oh you can run it up there for sure....i shot 130 hybrids out of a 24" 260 at 3050....shot 142s out of a 28" 260AI at 3020 and shot 105 hybrids at 3220 out of a 26" 6 creed...trust me its not worth it...the 142s in the 260 cases only lasted 2-3 loads a few only 1...the 130s at 3050 the barrel went at 650 rounds and the 6 creed at 3220 went 800 and started throwing flyers and at 850 was all done.

    its fun and if i had an unlimited supply of barrels id run a hot rod 6mm around 3200FPS....you just have to decide if its worth it.
     
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    Palmetto-Pride

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    Thanks guys for the responses. I probably will just see how far I can get her before I need to back off probably not something I’m going to continuously run all the time, just want to see what the limit is. The rifle is a AIAX with a 24 inch barrel.
     

    FreddyG

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    Whatever you do, don’t test the limits with hornady brass. It will fail spectacularly when it does. Not a good thing.
     

    Palmetto-Pride

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    Hi,

    Speed limits only exist if you are wanting to reuse the spent brass, if going about the notion that brass is a single use item then you can jump onto the Autobahn rather easily :)

    Sincerely,
    Theis
    Ha Ha yeah I am not to concerned about the brass life I have a ton of once fired factory 6.5CM brass.
     

    47guy

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    Ha Ha yeah I am not to concerned about the brass life I have a ton of once fired factory 6.5CM brass.

    your going to need better brass if you want to go fast...a couple of more inches of barrel will help too...RL16-17 and 26 and a long throat.

    ive blew a lotta heads off cheap once fired 300WM brass.
     

    Juggerxxx

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    Throw a bit of water on the outside of the brass right before you chamber a round. If you get heavy bolt lift or any other pressure signs then you know you are over or very close. I like to do this also because I shoot matches in rain and snow and learned the hard way in the middle of a match blowing primers in a snow storm. This was on a load that never showed any pressure sign even in 100 degree temps.
     

    Culpeper

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    Throw a bit of water on the outside of the brass right before you chamber a round. If you get heavy bolt lift or any other pressure signs then you know you are over or very close. I like to do this also because I shoot matches in rain and snow and learned the hard way in the middle of a match blowing primers in a snow storm. This was on a load that never showed any pressure sign even in 100 degree temps.

    Know your audience, dude.
     

    Fig

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    Sounds like you've been reading, "Hell, I was there!".

    I almost always pick a node well under the published maximums. If you can find a flat spot above that with no pressure signs then it's your prerogative, but just know that the further you push the less room for error there is. IMHO a compressed load helps when you are conducting evolutions like this. It takes that, "no room for error", and creates a little safe space. Plenty of powder for manbun that loads past 100%.
     
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    Culpeper

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    And that is why we don't play with matches or run with scissors. You should read that link above from 24 hour campfire. Or specifically this one post.

     
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    Gwain

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    I ran 144s at 2885 with RL16 in Peterson lrp brass. Pockets went after 4-5 firings. Barrel life was shit too. Great accuracy and hit like a hammer. Might have gotten a few more loads with srp brass. Was fun to play with. New barrel will be running 130s around 2930 and built a prc to run 153.5s.
     

    Dthomas3523

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    For what it’s worth, if I want to push something, I step up to the next case size. I understand this isn’t always possible. But things work out so much better when you’re not working on the fringes.
     

    bax

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    I am wanting to see how fast I can push my 6.5CM with Hornady 135gr A-Tips. I am up to 2840 FPS with 43.4grs of H4350 with zero pressure signs. I am going to load two rounds in .2gr increments until I start to see signs of pressure. I guess my question is at what signs do you put the brakes on and back off. Let me say I know different people tend to push the limit more than others and some people are ok pushing the boundaries a little further than others. I will admit I am the type that tends to push the limit a little, but also within reason (read not blowing myself or rifle up.....LOL) So what is your SOP when going for speed?
    1. If a case had a tight primer pocket before firing and after firing the fired primer falls out or you can push it out with your finger, that is too much pressure. Can depend on the case history. If it happens with a new case, that is probably bad but I had a batch of federal 223 cases that blew primer pockets with low-power loads and no other pressure signs.

    2. If the bolt closed easily on a loaded round but was hard to lift after you fire it, that is too much pressure.
    • In most cases the hard lift is because some of the case head flowed into the ejector cavity. The hard lift is you shearing off that brass. When you look at the case head, there is a round shiny spot where as you turned the bolt you sheared off the extruded brass. If you have soft brass this can happen with an otherwise safe load. If this happens with hard brass, stop shooting right now. Take all that ammo home and disassemble it - it is too hot.
    • With some bolt faces there is a raised lip of burrs created during manufacture - workmanship not so great. Take a hard tool and very lightly chamfer the edge of the ejector hole - you are trying to get burrs off, nothing more.
    • In other cases, firing the round pressure deformed the case head, made it larger and flatter, pressing it into the nooks and crannies of the bolt face. In that situation, twisting the bolt is not forcing the extractor hook around a normal case head (the normal thing), it is twisting the entire case in the chamber. When you open the bolt, the case may be stuck in the bolt face and you have to pry it out. The fired case head will be measurably larger than its correctly-fitting friends and have marks where it extruded into places where it wasn't supposed to go. This is a bad sign. You may see this together with blown primer pockets and extrusion into the ejector cavity.
    • You may be shoulder-bumping and neck sizing but not full-length sizing. Eventually your brass will expand to exactly chamber size and become difficult to extract just because the case body now tightly fits the chamber. In this case, the round may be difficult to chamber too. This is not a pressure sign. It is a hint that you need to dig out your full-length die.
    3. Case head significant crack or complete separation.
    • If this happens with a new case, there might be too much pressure. With not-new cases, there are "reloading sins" that can cause this - the principle sin being setting the shoulder back too far with fire-hardened brass.
    • With many-fired cases, you just stretched it too much. Except for maybe having to hinky around with the remaining part of the case or the significant chamber etch from high-temperature-pressure gas, you just wore out the brass. Pitch it and be happy.
    4. primer pocket cratering. Sometimes yes, sometimes no, and sometimes "yes, but doesn't matter". Some bolts crater federal primers with any load at all (like my 300 win mag) but not harder primers. Your 2-case photo shows primers without cratering or flattening - good. You can get other pressure signs and not cratering or you can get cratering (for example with federal primers) without other pressure signs. If you shoot a load and don't have cratering but as you increase your load you start to see it, that means pressure but it doesn't always mean excessive pressure. This is important: "no primer cratering" does not mean, "safe load".

    5. primer flattening. Depends on the gun, primer, powder, and load. I shoot Federal 205m, 210m, and 215m. They all flatten in all my guns, I stopped worrying about it 30 years ago. If "within guideline" loads show no flattening but when you go beyond max loads you get flattening, that means pressure - it may or may not be dangerous.

    For me, hard bolt lift is ALWAYS bad - at least with that brass. Blown primer pockets are almost always bad.

    It is fun to see how fast you can go but velocities above about 3,100 fps and pressures above 65k to 70k seem to really chew up barrels. If you do what you say you are doing, just plan on a new barrel. Its not a big deal and it isn't a ton of money but high temperatures and pressures chew out the throat and that means the gun won't shoot well. Like I said, it is fun but there is a price.

    Finally, I no longer bother with speed. I get my best groups and brass life and barrel life with moderate loads. I have several very expensive stainless steel tomato stakes as evidence that speed kills. Your mileage may vary.
     
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    Greg Langelius *

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    Another indication is that increases in powder charge do not result in increases in velocity. This is not always present, but usually accompanies at least some of the above indicators.

    If you see this, back off immediately.

    My philosophy vis-a-vis velocity is that it's a cruel mistress. The only velocity that's really valuable is reaching the target at above transsonic velocity, which I consider to be around 1300fps. Faster than that, neither you, nor your barrel need. I believe that counting on velocity to cancel drift is a false economy. No matter what velocity you're running, you still need to dope the wind accurately.

    My approach is to use long barrels. I don't use them to reach higher velocities, but to reach reasonable velocities with less pressure and heat acting on the bore. I run a 260 with a 28" barrel, and clock 2850fps or so with 140-142's. I bought that barrel and mounted it in 2003. That's 43.5gr of H-4350, or 45.5gr of H-4831SC in Starline or Hornady 7mm-08 brass necked partial length down to 6.5mm. It's a reliable 1Km rifle.

    Why 7-08 brass? Well, it's usually cheaper than 260, which is purely marketing BS; and because it's less popular, it tends to be available when 260 isn't. Why partial length neck resizing? lots of reasons, but mainly, my Older Brother taught me to do it.

    Greg
     
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    918v

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    Hi,

    Speed limits only exist if you are wanting to reuse the spent brass, if going about the notion that brass is a single use item then you can jump onto the Autobahn rather easily :)

    Sincerely,
    Theis

    Rifles have this particular relationship between the bolt lugs and the bolt recess in the action. If you do as you suggest, you will wear out your action, and for what?

    Minimal gains?
     

    THEIS

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    Rifles have this particular relationship between the bolt lugs and the bolt recess in the action. If you do as you suggest, you will wear out your action, and for what?

    Minimal gains?

    Hi,

    YOU may wear yours out. I can guarantee I will not wear mine out based on just the pure alloy selections alone.
    Also..you should be splitting cases long before you worry about wearing bolt lugs out.

    Sincerely,
    Theis
     

    Devildog

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    Do as you wish but I don’t understand the goal here. If you seek longer distances maybe a caliber change is in order. what you gain isn’t worth the risk or wear and tear on your rifle and in today’s world you might want to preserve your brass as long as you can. Just my 2 cents.
     

    Smittiac

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    Work up to pressure and back off to the closest safe SD/ES? Why try blowing up yourself to get 40fps? I can say Nosler LRP 6.5cm brass does not like that boundary lol popped a primer the other day whoopsies.
     

    918v

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    Hi,

    YOU may wear yours out. I can guarantee I will not wear mine out based on just the pure alloy selections alone.
    Also..you should be splitting cases long before you worry about wearing bolt lugs out.

    Sincerely,
    Theis

    If you load your brass to the point of difficult bolt lift and proceed to make that a “feature” of your ammunition, then you’ll wear out your bolt lugs no matter what alloy you choose for your action.
     

    brianf

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    If the material tensile and compression resistance is stronger than the pressure exerted by the cartridge as long as the lugs do not gall it will never fail

    most of the bolt lift issues is manipulation of the cartridge in the chamber not the lugs giving up


    think of a tennis ball against a tank.

    edit...gall not fail
     

    THEIS

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    If you load your brass to the point of difficult bolt lift and proceed to make that a “feature” of your ammunition, then you’ll wear out your bolt lugs no matter what alloy you choose for your action.

    Hi,

    You want to put money on that? We both send barreled actions to NTS testing facility in Camden Arkansas for high pressure ammunition fatigue/wear testing.

    We are currently at about 47k dollars in just alloy element analysis (Static and Dynamic) in deciding on alloy combinations to do what we are wanting to do---Run everything at 75-80k pressures with 2.5 safety factor. That is well beyond safety factor currently used today with lasts centuries pressure thresholds.

    Here is my bolt and breech cylinder alloy: Steel Aermet 100 | Tech Steel & Materials

    The Aermet 100 landing gear pin on the V22 Osprey shows ZERO dimension wear or fatigue stress in over 200k landings, nor does the engine pivot pins.

    Sincerely,
    Theis
     
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    Steel head

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    Hi,

    You want to put money on that? We both send barreled actions to NTS testing facility in Camden Arkansas for high pressure ammunition fatigue/wear testing.

    We are currently at about 47k dollars in just alloy element analysis (Static and Dynamic) in deciding on alloy combinations to do what we are wanting to do---Run everything at 75-80k pressures with 2.5 safety factor. That is well beyond safety factor currently used today with lasts centuries pressure thresholds.

    Here is my bolt and breech cylinder alloy: Steel Aermet 100 | Tech Steel & Materials

    The Aermet 100 landing gear pin on the V22 Osprey shows ZERO dimension wear or fatigue stress in over 200k landings, nor does the engine pivot pins.

    Sincerely,
    Theis
    It’s not like your wonder action is the norm.