max. +

[markmcj]

Have any of you guys worked past stated max levels in your reloading?

I'm working up some loads for .308 and have reached the max powder stats in my reoloading manual and have NO signs of pressure at all. Primers look great, bolt works free,no binding, exellent groups.

I'm having a tough time not trying to go for some more. Not all at once , but working up a tenth of a grain at a time. I'm a firm believer that the manuals are conservative to a point.

I know that this is a "at your own risk" thing and some will think it is stupid. Say what you will.

I'm of the thinking that to reload is to find a mixture that works great in your gun AND surpass factory ammo.

Just throwing a question out there.

By the way, right now I'm at 46.1 grains of N150 behind a 168gr. SMK. .560 at 100yrds just a hair over 2700fps.
At 46.1gr. I still have enough room for anther 1.5 grains of powder before compressing the load, which I do not intend to do.

In starting the load, 42 grains is the low end and I did see a steady increase in velocity to 46.1 grains. I feel the full potential of this load is yet to come.

Any thoughts?


mark mcj

 

[sricciardelli]

I've loaded N-150 From 36.3 grains to 47.0 grains using a Remington 9-1/2 primer. Just started getting pressure signs at 47.0

 

[C.R.Sam]

Bear in mind that primer appearance and extraction are NOT reliable overpressure signs.

If you persist in increasing the load......as soon as you get either less or more velocity than forcast based on your chrono data from the work-up loads.....back it down. Even if primers and extraction are still normal.

If you are not getting increased accuracy by loading up....back it down now to your most accurate load.

The tighter (better) the headspace.....the higher the pressure required to show primer signs. Same goes for the shape of the firing pin nose, clearance between firing pin an bolt etc etc.

If you are really unlucky, might not show pressure signs till you get into the 70,000 range.

Have fun, but don't juggle hand gernades.

And....remember that when you are loading to the edge....an increase in ambient or ammo temp over your test conditions can put you over.

Sam

 

[Johnny Guest]

Getting Way on Up There Already - - -

PLEASE NOTE:

Some of the loads mentioned in this thread are right at max according to the Speer #12 manual, and well over max in the Sierra #4--Only two references I have at hand showing N-150 with 168 bullets.

IF anyone feels the need to share specific data any higher that already given, please include appropriate BOLD FACE cautions regarding loads beyond published maximums.

Thanks for your cooperation.

Your friendly H&R Moderator,
Johnny

 

[HSMITH]

If you take a micrometer on the case heads you will see pressure signs much sooner. Extraction and bolt operation are not signs of pressure to use, when they come into play you are well over the highest pressures you should see. When the case heads expand over .002" STOP!!!!

 

[griz]

What do you hope to gain by going past the published max? If you’re only talking about 50 or 100 FPS then is it worth the decrease in the margin of safety?

In some lower pressure rounds (250 savage for example) I have gone past the max in a strong bolt action. In rounds such as the 308 however, I try to remember that the area between the published max and dangerous pressures is a very narrow path. Decide for yourself, but make sure you need or want to take the risk.

 

[Jeeper]

Ditto what was previously stated. I have never really seen a reason to go to such hot loads. There is nothing really gained by doing this. If you want more speed then get a different caliber. I load on the hot end but not to the extreme. The signs you mentioned are not really good measures for pressure.

 

[labgrade]

Good points & I've no argument with any, but too, stated max loads in reloading manuals are from their guns (likely test barrels, unless noted), using those exact components.

Any substitution of components (of which the rifle is certainly one of) changes the equation. THE reason why they always say start at 10% reduced & work your way up TO MAX PUBLISHED data. Too, one of the reasons why you may see a variance of maybe 2 full grains of the same components except the bullet = different hardness, length of engagement, etc. - they all add to friction/pressure - whatever ....

That said, I've taken at least one .30-06 load about 1.5+ grains over published max with zip for real pressure indicators. The load just kept getting tighter groups ... & BTW, these are once-fired cases & will be discarded right after firing. (FWIW)

Whenever (if) "pushing the limits," I'd suggest doing so only with that exact same lot of powder, primer, brass & bullet - any slight change in the combo can cause the whole shebang to go bust - bullet jacket a tad harder, primer a tad hotter, li'l bit thicker brass (internal dims less), etc. etc. & never work up anything even close to max in one rifle & shoot it in another without the whole "work it up" steps. I run "hot" in only one & they won't even chamber in the rest same caliber - way long throat.

Brings up one point .... longer throated rifles tend, only tend, mind you, to allow a bit extra leeway (sometimes) towards the upper end - sometimes. Each rifle, whether consecutive serial numbers or not, are unique & loads should be worked up in & dedicated to them exclusively if anywhere near the upper end. Obviously, there are those cases where someone has actually taken the time to ensure proper development in each & every one & they're all within safety limits ....

I too agree with the "if you need more," go with the next step up in caliber. I shoot a .308 Barnes 165 at 2400 fps - pretty measly & slow by most comparisons - but it kills elk all day long - kinda the whole point, no? If I "needed" much more, I'd go with an '06 & 180s, or 200s, or a .338 & a bit heavier.

Likely, the right blend for your particular application can be had by tweaking with components & staying within the published loadings.

Too, .002" head expansion is WAY, WAY over anything considered safe. Usual head expansion is in the ballpark of .0005-.0007" with NEW brass - soon as you start using that brass, it becomes work-hardened/embrittled & this method is less likely to show the pressure signs. I'd suggest a blade micrometer for this method, BTW = less likely to induce any measurement errors.

Ask Weshoot2 & Sam about that "when you lose velocity with extra powder" train of thought .... no chrony here, but it certainly sounds like they've got a real handle on when reaching max ....

 

[ms1200]

never saw a need to go past published max load. if i need more i would put the .308 back in the safe and pull out the .300 maggie

 

[C.R.Sam]

If TERRY MURBACH would step in would be nice. He currently workin with pressure test rigs. I think they are set up for both cup and piezeo. We mere mortals have to send out for testing. And I stay so low lately that I don't worry bout it. Accuracy economicaly is my biggie. I leave the lug busters to the kids.

All is not written in stone. Years ago Phill Sharpe sent loads from a batch to five testing labs. Results came back with somewhere around 10,000 cup difference from different labs. Five years later he sent more from that same batch to the same labs. Results, from each lab, were extremely close to the finding from the previous sampling. The extreme difference in results between labs was unchanged.

Sam

 

[markmcj]

I want to thank all that have replied to this post. Thanks.

I find it hard to take when it is said that the condition of the primer is not a sign of pressure. I use Federals{known to be the softest} when working up a load.
I have also kept track of the casehead measurements .007 under max listed.
This is slow processthat is taken in a meticulous manner.
Here, I find a chrono to be a fine piece of equipment, to see what is going on. Once the point of diminishing returns are meet, it's time to back off. As long as other indicators are in line.

I'm not looking to reinvent the wheel or come up with something never thought of before. I'm just looking to get the best preformance from the cartridge that I have decided to shoot. Isn't that what reloading is all about?

Again, I have no desire blow up my new rifle or lose a hand, which can be done with stupid methods.
I'm just posting a topic in a public forum to see if anyone else has worked up something that works for them. Something that I can work up to with my rifle.

To tell the truth, I'm looking at N550 to start working up some loads. It seems to get more velocity with the same amount of pressure levels.

Again, I wish to thank you guys for shedding some light.

mark mcj

 

[labgrade]

"I have also kept track of the casehead measurements .007 under max listed."

I hope you meant .0007" - a difference of 10X! yup, we reloaders can be way anal about this stuff. does matter.

Otherwise & if I misunderstood, please explain what you meant.

Far as using primers, marck, I usually do, as a pressure indicator. & me too having heard that Federal is one of the softest.

When a primer is blown "full-out" up against the bolt & there's absolutely zip for a outer radius, I'd say you are at the limits of your pressure curve.

Many say that primers are no indication of pressure, but I'd tend to differ. I'd think (mind you with absolutely zip for empirical data to substantiate this) that a primer with a nice & full outer radius would be "acceptabl" while one that was flattened against the bolt face with no outer radius would be "less so" ... if nothing else.

One of these days I'm gonna have to get a strain gauge/chrony combo & put it to the test.

 

[tomandnacole]

ive seen test results with a 22 cheatah. that put pressures over 80,000. the primer was still in good shape ( not flat no crater) keep in mind that this round uses small match small primer .308 cases, so surface area of the primer is less. on the other hand i have had expanded primer pockets with a max load in a 22-250 ack-imp, only with fronteer brass, wich is very soft. as you work youre load up you will find that one of the increases in charge (tward max) will actualy decrease velocity. in my experiance my best accuracy was found below that point. be carefull.
tom

 

[C.R.Sam]

The many variables involved preclude primer appearance being a reliable indicator of pressure.

Striker drives cartridge forward, primer ignites and while igniting the powder charge it backs out of the case untill it is stopped by the breach face. Then the powder charge, acting against the bullet, drives the case Base back against the breach face and over the primer....reseating the primer.

Very tight headspace with that individual cartridge will minimize the case movement and distortion of the primer.

Sam

 

[cheygriz]

I have exceeded book maximum in a few loads. Work up slowly. To my mind, the best measure of whether you're "over the edge" is how many times you can reload the case.

If I can't get 4-5 reloads out of a case, I feel that I've exceeded the max pressure that I feel comfortable with.

BTW: With certain powder/load combinations there is absolutely nothing wrong with a compressed powder charge. Some of my very best and most accurate loads are well below max pressure, but have HEAVILY compressed powder charges.

 

[WESHOOT2]

MY PRIMERS ARE PERFECT INDICATORS

When they blow or get pierced I figure I'm starting to get close to maximum.

"But there's still room for more powder.........."

I don't trust nuthin' but measuring cases, because I don't even trust THAT.
And, yes, I've blowed up one gun (actually, just bent).

Serious answer, yes, keep moving forward if that is your preference. Lord knows I do LOL.
Just be REAL CAREFUL as you exceed safe data, because you get to this creepy-crawly edge you don't even realize is there, often too late, for frankly not much gain.
Accuracy before speed..............

I accept increased wear-n-tear.

 

[HSMITH]

Take a sharpy marker and mic the case heads after loading, write the measurement on the case, then re-measure the case heads after firing when working up a load. Without pressure data this is the only acceptable way for me to determine when the pressure limits have been met. .002" is a LOT of case expansion, and time to stop. I have no issue with going slightly over max listed loads, all guns are different. I am very careful with signs of excessive pressure though.