7-300 Norma Mag Improved. IT’S ALIVE!!

[Dmagna]

Don't mean to get too far off topic on Huntnful's thread but how are you guys that are pushing the top end loads determining what the max charge weight is for your rifle. Are you simply looking for stiff bolt, ejector marks, flat primers, or are you measuring the case head before your brass is fired and checking the expansion of it after to see how much it grew.

I know with all the tough brass out there, and actions that are built to such great tolerances pressure can be difficult to spot at times. If you had a single shot action without an ejector, you wouldn't have that tell tell ejector mark to go by. By the time you had a stiff bolt in that scenario I'm betting you'd be way over pressure.

Just curious as to what others do to find their max loads, especially when playing with some of these wildcats.

Start low and work up, these big cases are more forgiving. I track speed, speed equals pressure. I can make an educated argument for where I think the speed should be for the given cartridge.

 

[Huntnful]

Are you monitoring or measuring your throat erosion during all this testing? It would be interesting to see the amount of throat erosion over the total shots fired….just for the heck of it and you are testing at your expense for us. lol.

My baseline case was a 180 ELDM at 3.590 COAL to the lands. After the first 50 rounds, it had not changed at all actually. I expected it to, so I checked it again haha.

Don't mean to get too far off topic on Huntnful's thread but how are you guys that are pushing the top end loads determining what the max charge weight is for your rifle. Are you simply looking for stiff bolt, ejector marks, flat primers, or are you measuring the case head before your brass is fired and checking the expansion of it after to see how much it grew.

I know with all the tough brass out there, and actions that are built to such great tolerances pressure can be difficult to spot at times. If you had a single shot action without an ejector, you wouldn't have that tell tell ejector mark to go by. By the time you had a stiff bolt in that scenario I'm betting you'd be way over pressure.

Just curious as to what others do to find their max loads, especially when playing with some of these wildcats.

I'm personally looking at primers, ejector marks, bolt lift and velocity. With more time behind it, and more firings on the brass, i'll get a better and better idea of it I think. As well as maybe more people shooting the cartridge.

I think getting unreal velocities, normally correlates to getting unreal pressure hahaha. But there isn't much info on this one out there to compare velocities to. So I will try to be realistic when I share them. And not just share a max load velocities with little bolt click for bragging purposes. I want realistic velocities, well under pressure with whatever powder.

 

[Huntnful]

63 rounds in. A little bit of cracking in front of the case neck. Nothing substantial past that. I'm sure it doesn't help that I'm fire forming with a hot burning powder, but I didn't want to use up my H1000 haha.

 

[Huntnful]

Did some more fire forming this evening. 12 rounds into a .6 MOA group at 108 yards.

Got a new triggercam to mess with also. Here's 3 of those 12 shots. Pretty stable before each shot breaks.


Then tested 180 ELDM's with 84gr. H1000. Shot a 5 shot group at 300 yards. ES of 6 over those 5 shots.

85gr. H1000 yielded 3225fps and didn't notice any pressure signs there either.

 

[haisardao]

Great results, a 180 gr bullet at 3190 will take care of business near and far.

 

[Quicksilver338]

Is the scope cam something you'd take hunting? I've always wondered about getting one for that. I usually spot all my impacts so getting that on video would be cool.

 

[Huntnful]

Great results, a 180 gr bullet at 3190 will take care of business near and far.

Absolutely agreed .

Is the scope cam something you'd take hunting? I've always wondered about getting one for that. I usually spot all my impacts so getting that on video would be cool.

I think it's definitely doable, depending on the hunt. That little sucker feels like it's 2lbs lol. And I wouldn't want it on my scope all the time. You'd have to keep it in your pack, and then put it on when you pursue an animal I'd think

 

[Quicksilver338]

Welllll….maybe not then haha. I bear hunt locally and the hikes usually aren't terrible. Probably the only time I'd take it along. At that point I've set up a spotter and phone skope before so choose your extra weight.

 

[Huntnful]

Welllll….maybe not then haha. I bear hunt locally and the hikes usually aren't terrible. Probably the only time I'd take it along. At that point I've set up a spotter and phone skope before so choose your extra weight.

Oh I would much prefer a spotter/phone scope video quality over this. This would only be a "cool" factor of seeing through the actual scope.

Or like in my cases last year, I was too close to the animals to do any type of videoing. So it would have been cool to just have it on and running while stalking in for sure.

 

[Huntnful]

Barrel has 85 rounds on it now. Lands have not moved. Still 3.590" COAL with a 180 ELDM. Just checked them.

 

[haisardao]

What bushing are you using to neck down your brass for the 180s?

 

[Quicksilver338]

Barrel has 85 rounds on it now. Lands have not moved. Still 3.590" COAL with a 180 ELDM. Just checked them.

H1000 is the ticket! I thinks it will be smart to just stick with that.

 

[Phil Rizzo]

I fired 5 rounds with a ladder today using 570.
My memory isn't the best but it's been refreshed now.
We may have to purchase carbon credits when using it!
.08 grs per log

 

[Huntnful]

What bushing are you using to neck down your brass for the 180s?

I'm using a .314 bushing, that takes my ID to about .282 and then I expand with a .2835 mandrel.

H1000 is the ticket! I thinks it will be smart to just stick with that.

Testing ES and speeds on some once fired with retumbo and N570 soon. But I really like H1000. Just gathering lots of data on this barrel, since I'll have another one chambered up for hunting season here shortly!

I fired 5 rounds with a ladder today using 570.
My memory isn't the best but it's been refreshed now.
We may have to purchase carbon credits when using it!

Hahahaha!! So true! It is some dirty stuff!