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Discussion Starter · #1 ·
Anyone using the Pressure Trace II system by RSI to obtain chamber pressures? I've been thinking about getting one and curious if any users have comments on the system. Based on their information it seems pretty accurate as long as you set it up properly but not sure how easy that is as it wants lots of highly specific information on your chambers and brass thickness. Any user feedback would be appreciated!
 

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Got to ask....why...? Usually chamber pressure if formulated by bullet weight,type,amount and burn rate of the powder. These figures are listed in most reloading manuals and have been formulated by ballistics experts in a shooting lab with the use of precise systems under controlled conditions.
Even with my experience during 45+ years of reloading 115-calibers,I have not had any occasion to question these published tables of chamber pressure's. To eliminate any false or misleading info when working up a load for a specific caliber,I always caution folks to start at a median load...mid way between minimum and max...to eliminate any safety concerns. Then after loading 5-rds...only 5-rds...fire them first to find any problems with the bullet and powder they have used. After checking for pressure signs...primer,case,un-burned powder,etc....then either reduce or increase load for better realiablty or accuracy.
To use an old axiom...why re-invent the wheel...? Or...if it ain't broke...don't fix it. To each his own...but I'm just an old retired G.I. and don't spend any time or money that I don't need to....LOL.
 

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The figures you get from the books are based on specific test barrels and components. There is a lot of variation due to the particular reamer used to cut your chamber, seating depths, primers and so on. If you are working up loads with non standard powders, bullets or primers your results won't be in the book. If you are working with an oddball cal like a wildcat you won't find much if any info either. Not reinventing the wheel....just using it for a different wagon.

A friend picked up one of the pressure trace II set ups and he said he had a lot of fun with it. Calibrating it was not simple but he's an engineer and has to over do everything. He wanted to get the calibration to match real numbers instead of just comparing data from round to round. To do that he made up a cap for each end of the barrel so he could plug the chamber and the muzzle and pump hydraulic fluid in. I think he picked up 3 points and used that to draw a curve. There is a thread on the NFATalk boards. You can search there for pressure trace and it should come up. I'm not sure if you have to be a member of the board or not.....Lots of good info there.

Frank
 

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Discussion Starter · #4 ·
Thanks, I will check out that site and see what I can find. After pressing loads together for over 40 years I find new tools that make reloading more precise and possibly safer, interesting. Long ago I used the published velocities in manuals, until I obtained my first chronograph and learned what I was missing, there's too many variables to accurately project this, even by the big guys. The information provided by pressure graphing could be helpful for not only safety but for efficiencies and accuracy purposes. Currently when components are hard to find, the reloader that isn't well stocked up may need to substitute components for something not specific in a manual, even a different brand primer has varying effects on pressures. It would be interesting to know these differences in my specific guns.

Reloading can be just as addictive as the belt fed fever and damn near as expensive when you start buying all the goodies and progressive presses. Anyone that asks me if they can save money with reloading I always tell them probably not but it allows you to shoot a hell of a lot more!
 

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Usually answer same question of $$$ savings by loading your own...'For every dollar spent on commercial ammo,you can usually have 3-5 times more ammo for the same cost"...after amortizing and depreciation of your equipment. Kudo's on your quest to make better ammo. Only caliber that I spend extra time and energy to reload is .50 BMG. Otherwise,all the rest are loaded with a median load for that weight bullet and powder for basic safety and reliability.
 

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I do a lot of loading to feed some long range target rifles, subguns, pistols and cannons I can't buy ammo for and so on. I used to load 50 BMG because I didn't trust a lot of the ammo on the market. At one time it was possible to save quite a bit by loading your own but with the cost of commercial components its pretty tough to save much when you include your time. The days of cheap surplus ammo and components is over.

In learning tricks to improve accuracy for the long range guns I've found that most of my rifles can shoot a lot better when ammunition is tailored for them with seating depth, powder type and charge, bullets and so on. Some of my semi autos can be much more accurate with ammo loaded just for them as compared to commercial or generic hand loaded ammo. So for me the loading is a lot more than just supply. Its a way of improving over what else is available. Each has their own reasons.

I have found quickload to be a decent source of information. Its not precise because the number of variables is huge and the ability for the average joe to measure them is not always good. We can measure velocity pretty well and correcting the quickload numbers to match your observed velocity can help you get more accurate info from the program. Combining the quickload with the pressure trace II system might get you better yet. All it takes is time, money and an interest in doing it. I'd love to fiddle with the system but time is tough to find for those kinds of projects. Maybe you can put it all together?

Frank
 
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