Reloading- What pressure signs do you stop at?

[VinceMule]

I wear these when hunting:

Peltor Sport Tactical 100 Electronic Earmuffs (NRR 22dB) Black

Featuring proprietary 3M technology that surpresses harmful gunshot noise while amplifying low-level sounds, the 3M Peltor Tactical 100 Electronic...

www.midwayusa.com

Keeps my ears warm also. At the range, I use foam ear plugs and the Peltors, and hear on a level of normal conversation.

Any brake with 5 degree or more slanted ports will reduce concussion on your head. If the ports are slanted to the rear, concussion is greatly increased.

 

[SheepShapeAK]

I just stop at case head separation. Then back down .01 grains of powder.

 

[Rosebud]

Had a CZ550 in 6.5x55. Pushing a 140 Berger VLD at 2975. I killed enough critters to bury a full sized pickup. White tails, antelope, muledeer. Over about twenty years. Yes I knew I was pushing it to hard. But the CZ action could take it easily. The brass , that was another matter. After about 6 or 8 loads the primer pockets were toast. After about 2800 or so rounds the lead was also toast. That's when the 6.5 CM showed up. My old swead was retired.

 

[VinceMule]

Rosebud, the sierra 140g sptbt game king may revive the accuracy of the old sweede, those long throats are often not getting their best accuracy with a VLD bullet whereas a bullet with more bearing surface may bring back accuracy. We have seen this "more bearing surface" issue fix a lot of the family's barrels with worn throats. Best of luck to you!

 

[Mr. Magoo]

I've said it before but I'll say it again for the newer reloaders if they've made it this far:

Using the pause or jump you'll see in chronographed speed increases doesn't necessarlily mean you have found the usable pressure peak for your brass. If you're not seeing ANY other pressure signs, it just means that you either found a node, or are getting out of one.

Anybody that has done a ladder test knows this.

There are 2 different reasons pressures fail to increase with each small increase of powder. The first one is a little above above my ability to explain, and involves rocket science. It is called the node and you want to be in the middle of it for best accuracy and consistency as long as you're not seeing traditional pressure signs such as flattened/ cratered/leaking primers (case head expansion, primer pockets loosening up & hard bolt lift means youve hit plastic limits of the brass and you shold back off a grain or more, and access why- wet brass or a wet chamber decreases the usable chamber expansion volume and will make pressure spike) ejector swipes, (all the normal stuff talked about here already). However, if the velocity is near or above published book values you should be cautious, pay attention, and probably not proceed. But I would not stop exactly AT a large velocity increase at published top speed- I'd back it down to the velocity pause that likely came before it if the primers and base of the brass still look good

The second is when you've reached the plastic limit of the the brass which makes the usable volume of the chamber change permanently upon firing- I. E. The brass did not spring back. That is a hard limit you should never go past (or even stay at).

This is why putting too much stock in speed increases (or lack therof) isn't as good for finding the pressure peak limit of the brass as signs that crop up earlier such as primer condition, unless you don't mind trashing a few pieces of brass and getting a little on the dangerous side. At that point, you've already ruined your brass' usable life.

So to reiterate for new reloaders: this is why I say look at 'all the above' for reading pressure. If you back off from from a load only because of a velocity pause, without seeing ANY other pressure signs, you've probably discarded what was potentially an accurate load.

 

[Dean2]

Magoo - I agree with a lot of what you posted but the most salient point is, If you hit a velocity plateau at or above normal published velocities, stop immediately, even if there are no other pressure signs. If you hit a plateau well below max published velocity, you may well of hit a node.

Many loads show no pressure signs at or a very small amount above published velocities. By the time you are seeing most common signs of high pressure, you are well above the Saami rated pressure limits.

 

[Mr. Magoo]

Magoo - I agree with a lot of what you posted but the most salient point is, If you hit a velocity plateau at or above normal published velocities, stop immediately, even if there are no other pressure signs. If you hit a plateau well below max published velocity, you may well of hit a node.

Many loads show no pressure signs at or a very small amount above published velocities. By the time you are seeing most common signs of high pressure, you are well above the Saami rated pressure limits.

I agree with that..much clearer and shorter than the way I put it.

I was mostly trying to illustrate that the 'velocity increase' method of "pressure detection" is not entirely accurate (and think I failed to, even with all those words haha)

Edit- After thinking about it some more, I need to add another exception to the above velocity advice for the newbies- and that is: velocities may be different than top book velocities if you have bullets with less engraving pressure (Absolute Hammers come to mind), or barrels lengths that vary significantly from the barrel used in the published data. Even a gas piston operated rifle may differ in velocity even if barrel length is the same (it depends on the timing)

So still another reason not to put so much stock in velocity.

 

[Mike Matteson]

I do a powder increase, and depending on what are the normal charge in a case is, sets the rate of increase. Under 60grs I go up at about .25grs at a time., If the case hold about 70grs+ I move up .05grs at a time. I start out the the low powder charge in the manual. (I do look at several manual to see what different there is). I load a single case with that powder load and mark it. Increase by the amount stated above in a single case. I'll have 10 -15 cases loaded with the increase powder. Also get in ladder test at the same time. I'll go up and generally above the max load shown in the manual. Some of my loads are 5 to 6 grs over max load shown. In my heavier calibers I am looking a 3300fps. Smaller calibers I am looking at higher velocities.
I Watch the primers to tell me where I am at. I also watch for ejector marks, and heavy lift. It's not to often that I even get to creatoring the primers. I know that others go to heavy lift, and or ejector marks. I don't! I generally use single based powders. Most single base powders aren't as effected as much by temperture. All Powder are all subject to temp.
So if you are using a double base powder and hot loads. Better check in the different times of the year. If develop in the cold weather, need to reduce the load and start back up in the hotter weather. Or the other way from hot to cold weather.
I am after max velocity and grouping of about 1/2 @ 100yds and see how they are doing at 300, 400 and 500yrs. I generally don't have a grouping problem with that.
If the rifle doesn't group need to change the loads, and or more work needs to be done to the rifle. Bedding, Trigger, float the barrel and few others items. There can be other problems.

 

[VinceMule]

good post, Mike!

 

[dundonrl]

I went one grain over Noslers published data on my 375 RUM. 97 grains IMR-4350 firing their 260 gr Accubond and 95 grains IMR-4350 with a 300 gr Partition using Federal 215 primers. I don't get any signs of excessive pressures, but through my Chrony beta I'm getting right at 3200 FPS with the Accubond and 3000 FPS with the Partition. (Remington 700 with 28" Pac Nor Super Match grade chrome-moly steel bbl) I'm sure I could go higher, but the recoil is already beyond ridiculous even with a 1" mercury tube and limb saver recoil pad.

 

[Mike Matteson]

I went one grain over Noslers published data on my 375 RUM. 97 grains IMR-4350 firing their 260 gr Accubond and 95 grains IMR-4350 with a 300 gr Partition using Federal 215 primers. I don't get any signs of excessive pressures, but through my Chrony beta I'm getting right at 3200 FPS with the Accubond and 3000 FPS with the Partition. (Remington 700 with 28" Pac Nor Super Match grade chrome-moly steel bbl) I'm sure I could go higher, but the recoil is already beyond ridiculous even with a 1" mercury tube and limb saver recoil pad.

That pushing then down the tube. I never had looked a 375 RUM. That moving to me. That is the area I like my velocity at, in 308 NM and 338W Mag. 165gr and 200gr Noslers.
You need a real brake on it.

 

[Rosebud]

Rosebud, the sierra 140g sptbt game king may revive the accuracy of the old sweede, those long throats are often not getting their best accuracy with a VLD bullet whereas a bullet with more bearing surface may bring back accuracy. We have seen this "more bearing surface" issue fix a lot of the family's barrels with worn throats. Best of luck to you!

The thing had a huge lead to begin with, thought about a new barrel, or set back. But at the time the mausers components were not available. I needed new brass and couldn't find the bergers anywhere. CM brass and ammo was everywhere. May have it work on it one day.

 

[264WM]

With my 264WM I stopped at flattened primer and extractor marks on the casing. That was a 160gr Woodleigh PPSN moving at 3267fps using Hodgen H570 using 73gr. Book says 71gr at 3067.

 

[memtb]

I went one grain over Noslers published data on my 375 RUM. 97 grains IMR-4350 firing their 260 gr Accubond and 95 grains IMR-4350 with a 300 gr Partition using Federal 215 primers. I don't get any signs of excessive pressures, but through my Chrony beta I'm getting right at 3200 FPS with the Accubond and 3000 FPS with the Partition. (Remington 700 with 28" Pac Nor Super Match grade chrome-moly steel bbl) I'm sure I could go higher, but the recoil is already beyond ridiculous even with a 1" mercury tube and limb saver recoil pad.

What is the weight of your RUM……scoped, loaded, and slung? Is it for hunting or extended long range shooting sessions? Enquiring Minds! memtb