Shooting to 1000m with 20 inch barrel.

That's a great picture. You must have a decent camera.

I made a correction in my last post. I'm burning 46.75gr of Varget. I'm sure the pressure is down a bit from what you guys figured out but there are so many factors in what you're trying to calculate I commend you on trying to figure all that out.

I guess I should add that I use Gun Juice in my barrel religiously and from the time I started using it, when the gun was brand new till now, I've noticed something in the barrel that I've never witnessed with anything else I've used. The barrel has taken on an almost clear coat finish and bullet velocities are obviously higher then normal out of my Rock Creek barrel.
 
kombayotch said:
Some 30-06 cases with CCI 200 primers:

Img_7487.jpg

57k, 62k, 66k, 70k, 74k psi

CCI primers are pretty hard...
Click to expand...

I love the 'rma' on the headstamp.

A wee bit toasty me thinks...

Or maybe a bolt face that needs to be polished some more:D

We need simple, inexpensive and accurate/reliable, pressure trace gear.

Jerry
 
kombayotch said:
Some 30-06 cases with CCI 200 primers:

Img_7487.jpg

57k, 62k, 66k, 70k, 74k psi

CCI primers are pretty hard...
Click to expand...

Case 3 you can see extrusion of base into ejector hole starting, and case 5 it extruded enuf to shear the brass. Cases 3 and 5 were nearly indexed the same in the chamber.

I have several of my Remingtons with pinned ejectors and and .062 holes and firing pins, so that I can handle more pressure. Lapua brass usually is harder than Norma. I've been told Norma uses 1 more annealing operation than other manufactures

NormB

On further inspection and comparing primer pocket rings the case #5 with 74K is slightly smaller and blacker and looks like it leaked gas from the sheared brass area around whole primer. Custom actions with ejectors further out near the rim of the case should handle pressure better. Remington ejectors and large primers are very close together. Savage pins are not quite as large in dia. Custom actions with ejector pins part way into bolt head ring should also have more leverage to eject cases. Extrusion into ejector hole noticeable at 66K. Sure looks like a Rem bolt face.
 
Last edited:
though my primers are definitely more flat then round, I haven't lost the Lapua writing yet and probably won't. If you want to rework the calculations based on the amount of powder I'm pushing and let me know how much pressure I'm running, I'd find that interesting.
 
Some where a definition of overbore comes to mind (with variables such as chamber and bore volume, bore dia, amount of powder, weight of bullet). Sure, you can do it with a short barrel, but not without costs. I read that reloader 17 can provide you a boost in velocity too, probably designed by a great engineer looking to make magnums out of standard cartridges. Would I be acurrate in saying this? Also, would it be accurate to say that the rail gun guys with short barrels are not there to achieve high V, but grand Aggs?
 
I have no issues pushing the 175 SMK out of a 20" barrel and hitting the steel at 1000meters, I run Winchester cases ,210M primers and IMR 4895 powder and I am getting a sub MOA load at 2630 avg
 
Glock-a-maniac said:
though my primers are definitely more flat then round, I haven't lost the Lapua writing yet and probably won't. If you want to rework the calculations based on the amount of powder I'm pushing and let me know how much pressure I'm running, I'd find that interesting.
Click to expand...

As I said before, case appearance is a lousy way to determine pressure in your rifle.

how hot you run it entirely up to you BUT suggesting it is SAFE ie within SAAMI limits, without pressure trace info may not be ideal practise.

Re 17 has been used in a handful of combinations to provide additional speed WITH accuracy. I never got it to shoot in my 6.5's. Some heavy 6mm combos seem to work and heavy 308 combos might too.

Load data from Alliant does not show Re17 to be a super powder in anyway.

New stuff coming out now does show alot of promise. Not because it is some magic fuel but because you can physically get more of it in the case.

I will do more testing as the snow melts.

Jerry
 
Glock-a-maniac said:
That's a great picture. You must have a decent camera.

I made a correction in my last post. I'm burning 46.75gr of Varget. I'm sure the pressure is down a bit from what you guys figured out but there are so many factors in what you're trying to calculate I commend you on trying to figure all that out.

I guess I should add that I use Gun Juice in my barrel religiously and from the time I started using it, when the gun was brand new till now, I've noticed something in the barrel that I've never witnessed with anything else I've used. The barrel has taken on an almost clear coat finish and bullet velocities are obviously higher then normal out of my Rock Creek barrel.
Click to expand...

46.75 grains of Varget on the Quick load program will give you 70,558PSI.
Cat
 
Quickload's pressure estimates for Varget are high, at least in match barrels...

46.75 is probably somewhere around 65k psi with bare bullets. If he's using a product that reduces friction, it's probably several thousand psi lower... Still hot, but not at all unreasonable.

That Gun Juice sounds like it could be useful with subsonic loads.
 
kombayotch said:
Quickload's pressure estimates for Varget are high, at least in match barrels...

46.75 is probably somewhere around 65k psi with bare bullets. If he's using a product that reduces friction, it's probably several thousand psi lower... Still hot, but not at all unreasonable.

That Gun Juice sounds like it could be useful with subsonic loads.
Click to expand...
I don't think gun juice is used in the chamber , is it?
Cat
 
It isn't the chamber that matters, it's the bore.

http://www.microlon.com/gun_metal_treatment.php

Microlon Gun Juice cleans and treats your firearms. It is far superior to oils because it provides excellent lubrication and is a "Dry Film" lubricant that will not attract dirt, dust or grit which can permanently damage a firearm. It increases muzzle velocity, improves accuracy and consistency, reduces wear from friction and prevents rust and corrosion.
Click to expand...

Sounds similar to moly or hBN, but applied to the bore, instead of the bullets.
 
Chamber pressure isn't limited to the chambers, it is constant from the inside of the case to the base of the bullet. And the bullet gets pushed down the bore before that pressure peaks. So yes, lubrication in the bore does reduce peak chamber pressure.
 
kombayotch said:
Chamber pressure isn't limited to the chambers, it is constant from the inside of the case to the base of the bullet. And the bullet gets pushed down the bore before that pressure peaks. So yes, lubrication in the bore does reduce peak chamber pressure.
Click to expand...
That being said, it would peak faster with different powders, right?
The big question is just how far down the barrel goes before the peak pressure is reached - I know I do not have the money that is needed to buy that kind of equipment!!:eek:
Cat
 
Yes, it will peak faster with faster burning powders, with bare bullets, with heavier bullets, with a tighter bore, with a hotter primer, in hotter temperature (with traditional powders)... basically anything that increases friction or increases the powder burn rate.
 
kombayotch said:
Yes, it will peak faster with faster burning powders, with bare bullets, with heavier bullets, with a tighter bore, with a hotter primer, in hotter temperature (with traditional powders)... basically anything that increases friction or increases the powder burn rate.
Click to expand...
Yup, I realize all that matters - i STILL don't have the scratch for that kind of pressure equipment!!:D
Cat
 
It actually saves money in the long run if you develop a lot of different loads. It only takes me 5 rounds to have a very good idea of where maximum pressure is with a load. And when it's tuned properly, I also know where the OBT nodes are and can run a small OCW test at those locations to pinpoint them.

Also, issues like donuts and carbon rings are easily detected.

It's an investment, and it's paid for itself several times over for me. And I'm not shooting anything like a 338 LM, which it would definitely be worthwhile for.
 
kombayotch said:
It actually saves money in the long run if you develop a lot of different loads. It only takes me 5 rounds to have a very good idea of where maximum pressure is with a load. And when it's tuned properly, I also know where the OBT nodes are and can run a small OCW test at those locations to pinpoint them.

Also, issues like donuts and carbon rings are easily detected.

It's an investment, and it's paid for itself several times over for me. And I'm not shooting anything like a 338 LM, which it would definitely be worthwhile for.
Click to expand...
Okay, HOW MUCH??!!:p
PM me......:D
Cat
 
NormB said:
Lapua brass usually is harder than Norma. I've been told Norma uses 1 more annealing operation than other manufactures

NormB
Click to expand...

The Norma reloading manual has their brass composed of 68%Cu, 32% Zn, which is softer than most others, who are using 70/30 mix (have not seen anything to verify this from specific manufactures, but the term Cartridge Brass C26000 uses a 70/30 mix), plus cold working for hardness.

Three annealing phases and one stress relieving phase seems to be the current standard on making brass cartridges.
 
scout said:
The Norma reloading manual has their brass composed of 68%Cu, 32% Zn, which is softer than most others, who are using 70/30 mix (have not seen anything to verify this from specific manufactures, but the term Cartridge Brass C26000 uses a 70/30 mix), plus cold working for hardness.

Three annealing phases and one stress relieving phase seems to be the current standard on making brass cartridges.
Click to expand...

A columnist for Precision Shooting magazine, who toured the Norma Plant several years back, wrote an article extolling the virtues of Norma Brass. He didn't mention the softness issue, which I find a problem in general and with Norma 6 PPC brass in particular.I tried some at the Supershoot, when it first came out. It was dimensionally near perfect, but wouldn't stand up to the pressures that my Lapua brass did. So I phoned him about it. He put it down to 1 more anneal process in Norma's production process.

Maybe they have changed, or he got it wrong. I've still got that brass untouched for years sitting in my cabinet, the only Norma I have.

NormB
 
You must log in or register to reply here.
Back
Top Bottom