QL request, 7mm-08 and 162 Eldx

[highoctane]

Ok I just looked at the Hammer Hunters online forum load data. Varget was IMPRESSIVE with 3130fps@26" barrel, that is until I looked at Staball 6.5 velocity numbers. Holy sheep shyt 3250fps!!! With a 132gr!!! So let's say I shoot a 22" barrel, so subtract 100-120fps ish. 3100 is smoking! My original thoughts were 2900-2950 fps wow! Color me impressed!!!

What you see from others when it comes to velocity may or may not transfer to your rifle. Just to be honest, unless you know or have some sort of connection with this trove of data you had better be careful.

Case in point, my 280 Rem will digest 57 grs of IMR 4831 and spit a 139 gr SST bullet 2930 fps, however, 58 grs of same 4831 and same 139 gr bullet shows ejector marks and sticky cases but if you do a little research you will find many instances of those saying 58 grs is perfectly fine. It wasn't fine in my rifle.

Do your due diligence and work your load up with a chronograph. Primers are not a reliable pressure indicator. Once you see catering, flattening and such you are WAY OVER PRESSURE most times, sometimes exceeding 70,000 psi. That kind of pressure if it gets loose because a case failed is "gonna leave a mark"

 

[Aussie Wanderer]

Ok I just looked at the Hammer Hunters online forum load data. Varget was IMPRESSIVE with 3130fps@26" barrel, that is until I looked at Staball 6.5 velocity numbers. Holy sheep shyt 3250fps!!! With a 132gr!!! So let's say I shoot a 22" barrel, so subtract 100-120fps ish. 3100 is smoking! My original thoughts were 2900-2950 fps wow! Color me impressed!!!

That sounds like peak alloy stuff. There is that expression, "just because you can, doesn't mean you should." I would hazard a guess that those velocities are way over max saami pressure

 

[RL338]

I’ve tried some of the Hammer load data and I can’t get nowhere near their published data. I’m thinking they’re opening the bolt with a dead blow hammer , hence their name Hammer Bullets

 

[sticks]

I’ve tried some of the Hammer load data and I can’t get nowhere near their published data. I’m thinking they’re opening the bolt with a dead blow hammer , hence their name Hammer Bullets

That's a good one RL338!

I just watched a great video on YouTube, from a channel called "TherealGunsmith" on case head expansion and pressure. Brass is the weak link in the equation. Every brass manufacture is different in thickness, metallurgy, process, treatments, ect. He was measuring his case heads just above the extractor groove, said to mark a couple spots, and remeasure those same spots after firing. He only accepts .0005" expansion, anything past this he reduces the load. Keep in mind that's .0005" just at the base of the case head not the body of the cartridge. I think he recommended a ball micrometer over a flat. Nobody without a strain gauge, piezo electric dodad knows exactly what pressure they are at, using flattened primers, loose primer pockets, ejector marks, and extractor swipes as pressure indicators, and are probably a good bit past the mark at that point. High quality brass, smaller or tighter primer pockets, 40 degree improved necks can hide overpressure. I think from now on I'm going to implement case head expansion measure in my development routine. I do stick to published load data from reputable sources and I like to stay on the safe side by about .5 - 1 gr, and I don't like compressing beyond 103-105%. Interested if there is anyone measuring case head expansion and their thoughts, I've heard of it before, but today I finally decided to investigate.

 

[Aussie Wanderer]

Sticks this is what the majority of reloaders in Australia would use as their first port of call when it comes to loads and pressure. It is also probably one of the great frustrations in that it very rarely gets to maximum SAAMI pressure which I think puts more handloaders at risk than had they gone to maximum. Many handloaders will go over seeking to get to that max without any real knowledge of what that pressure actually is. Unless you have all the tools as you mentioned, the science behind handloading for the majority of people might be closer to witchcraft

Data – Rifle

Whenever practicable, avoid loading to maximum possible velocity. Safety Data Sheets include all information relating to product composition, safety, handling and storage.

www.adiworldclass.com.au

 

[Wolfshead]

I know that my experience isn’t 7-08, but talking of 130 grain projectiles has me thinking this might fit.
I shoot the 130 Barnes ttsx out of my tikka .308 Win, with a 20” barrel, at an average velocity of 3170 fps using Ramshot TAC.
The max load is 51.2 grains, I’m shooting 50.4 grains.
While developing my load when I got close the max listed I was having stiff bolt lift around 51 grains.
At 51 grains velocity was around 3230 fps.
Varget was giving me velocities around the upper 2900’s.
Out to my limit of 300 yards TAC is helping to make my 308 shoot like a 270, with almost a whole grain less than max

 

[jimbires]

That's a good one RL338!

I just watched a great video on YouTube, from a channel called "TherealGunsmith" on case head expansion and pressure. Brass is the weak link in the equation. Every brass manufacture is different in thickness, metallurgy, process, treatments, ect. He was measuring his case heads just above the extractor groove, said to mark a couple spots, and remeasure those same spots after firing. He only accepts .0005" expansion, anything past this he reduces the load. Keep in mind that's .0005" just at the base of the case head not the body of the cartridge. I think he recommended a ball micrometer over a flat. Nobody without a strain gauge, piezo electric dodad knows exactly what pressure they are at, using flattened primers, loose primer pockets, ejector marks, and extractor swipes as pressure indicators, and are probably a good bit past the mark at that point. High quality brass, smaller or tighter primer pockets, 40 degree improved necks can hide overpressure. I think from now on I'm going to implement case head expansion measure in my development routine. I do stick to published load data from reputable sources and I like to stay on the safe side by about .5 - 1 gr, and I don't like compressing beyond 103-105%. Interested if there is anyone measuring case head expansion and their thoughts, I've heard of it before, but today I finally decided to investigate.

Yes , I have watched casehead expansion . it is tricky , since you are watching for such a small difference in measurement . you need to use a " blade micrometer " . and measure from the same place on the case head . I shoot a lot of 7mm stuff , so I'll put the one micrometer blade at the " 7 " on the head stamp . I use once fired brass , and the expansion needs to be less than , 0.0002" this is 2 tenths of a thousandths . a very very small number . it can be hard to get a repeatable measurement , it's so small . but yes , it's another tool for watching for pressure . I "THINK" there is a good write up in my one manual on doing this , I'll look . if I have the info , I'll post it up for you .

what I've been doing if I think I'm pushing pressure is , I'll load one case , over and over . I just go in my backyard and fire it . if the primer pocket is still tight after 4 or 5 firings , I feel the pressure is acceptable . as long as there are no other pressure signs . if you can feel the new primer seating easier each cycle , you're over pressure .

 

[jimbires]

one thing I forgot to mention is , if working with a belted case , you will measure head expansion right on the belt .


I found the info in my book , for you .

you will need a " Blade Micrometer " to measure this .


a "BALL Micrometer is more used for measuring neck thickness . here's mine with a modified anvil to be able to measure up close to the case shoulder . you can see it would not be the choice for measuring casehead expansion .



here is the info from my book . you were correct on the 0.0005" spec .



cut away case drawing to show how the case head is solid , right above the extractor groove .

 

[sticks]

Wow thank you for posting that... I like your approach of firing multiple rounds in a single case and checking primer pocket fit. Finding out in a day what could take months or years. Great info on using a "blade" micrometer, and also using "once" fired brass that hasn't been case hardened to get the correct headspace expansion results. Wow, how are more people not doing this?

 

[jimbires]

Wow thank you for posting that... I like your approach of firing multiple rounds in a single case and checking primer pocket fit. Finding out in a day what could take months or years. Great info on using a "blade" micrometer, and also using "once" fired brass that hasn't been case hardened to get the correct headspace expansion results. Wow, how are more people not doing this?

like I said , this measurement is so small that it's hard to get repeatable numbers . I'm not a machinist , but I did use these more than the average guy . I have a hard time getting repeatable measurements . if you venture into this , you'll see what I'm saying . but with all this said , it is another tool to use to watch for pressure . I've thought about making a jig to hold the fired case , that would allow both hands to work the micrometer . a small block of wood with a dowel rod sticking up would be about all one would need . I use my loading tray , but it's not great , too much flopping around .