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Post by ET on Jul 22, 2019 20:14:45 GMT -5
After giving this, some thought I have come to my own conclusion. Here is my line of thinking. When we look at a loading manual for a rifle, we are given bullet-powder and weight-resulting peak pressure and velocity. This is intended to produce safe loads. Kind of sounds very familiar with PT results for peak pressure that have velocity included for SML. Two advantages we have here is seeing the pressure curve response and any abnormalities such as secondary spikes.
We often refer to the SML PT’s as a guide line but doesn’t the rifle loading manual represent the same thing? Question some may be pondering about is the accuracy of SML PT results. That is dependent on operator’s diligence, understanding his equipment functions and experience. The PT manual can provide support to the later 2 mentioned. So my question is do we consider PT’S as a guide line or can we see it as a developing Loading Manual for SML?
I’m hoping for a good discussion and not a battle royal with chosen sides.
Ed
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Post by joelmoney on Jul 22, 2019 23:50:45 GMT -5
I think we are in a sense writing the manual or manuals to SML. But just as in cartridge reloading I like to use multiple sources. Multiple sources are each persons pressure traces, quick load, and what is working for others. I think there are lots of great loads that have not been shared yet.
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Post by dannoboone on Jul 23, 2019 11:49:23 GMT -5
After giving this, some thought I have come to my own conclusion. Here is my line of thinking. When we look at a loading manual for a rifle, we are given bullet-powder and weight-resulting peak pressure and velocity. This is intended to produce safe loads. Kind of sounds very familiar with PT results for peak pressure that have velocity included for SML. Two advantages we have here is seeing the pressure curve response and any abnormalities such as secondary spikes. We often refer to the SML PT’s as a guide line but doesn’t the rifle loading manual represent the same thing? So my question is do we consider PT’S as a guide line or can we see it as a developing Loading Manual for SML? I’m hoping for a good discussion and not a battle royal with chosen sides. Ed Personally, I use TG's PTs as both a guide line and for load development. Detesting muzzle brakes, my shoulder gives out before pressures become dangerous with MOST loads. There are so many variances in SML that do not exist in center fire. One sabot goes down with one hand pressure and another requires two hands. Few people are going to get the equipment to measure said pressure. Same with those of us with .45's who size our own bullets, and yet there would be another difference in smooth forming verses full forming. Those who develop loads for the CF manuals are using bullets which vary a very few hundreds of thousandths at most. That isn't necessarily the case with SML.
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Post by ET on Jul 23, 2019 15:04:22 GMT -5
I think we are in a sense writing the manual or manuals to SML. But just as in cartridge reloading I like to use multiple sources. Multiple sources are each persons pressure traces, quick load, and what is working for others. I think there are lots of great loads that have not been shared yet. Interesting response and like the approach of not being fixated on one source for info. Ed
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Post by ET on Jul 23, 2019 15:34:50 GMT -5
Dannoboone you made some interesting points to take into consideration. Like you I use it more as a guide to remain in what I deem a safe pressure range. With a loading manual they give you what they recommend as a safe max pressure level. In SML there is no established safe level for max pressure other than what a barrel manufacture can provide. From my view point I see two groups where a peak pressure can be divided. The 40k and under as to the over 40k that still has not established limits. Here the individual has to decide what he feels comfortable (safe) with. The one good point of PT's they have taken away a somewhat blind spot and allows us to move cautiously forward in further load development.
Ed
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Post by joelmoney on Jul 23, 2019 22:12:32 GMT -5
I like multiple sources in my cartridge reloading also. If multiple sources agree I feel much more comfortable. There can always be typos and misprints. Multiple sources that agree eliminate screw ups in my book. I also use rough extrapolation out of reloading manuals as a way to get a rough idea for loads I want to investigate further.
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Post by Earnhardt on Jul 24, 2019 8:10:50 GMT -5
Having Quickloads, I very seldom read reloading manuals for loads/pressures. With all of the variability in bullet design, freebore reamer specs and the like, Quickloads is now my go to guide for reloading. With that said, the same goes for SML reloading. FOR ME, I try to use 50,000 as my max load for a SML. Why? FOR ME, It gives me a little piece of mind when it comes to "room for error". One of the nice things, is that with SMLs, the vast majority of them are from .400 to .458 caliber, and there are quite a few powders that can give you a max psi from 45k to 50 kpsi. You can slam that .45 300 grain bullet with 70 grains of H4198, or you can dump an obsene amount of Reloder 16 down the barrel, and the pressures will be relatively the same.... But the velocities are extremely different. Ranging from 2700 fps with H4198, up to 3200 fps with Reloder 16. Keeping the pressures between 45-50,000 psi is easy...but with a fps swing from 2700 to 3200 fps, the only variable is how much you want your shoulder to hurt after pulling the trigger.
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Post by ET on Jul 24, 2019 19:08:02 GMT -5
First my Thanks to those who have responded to this post. Just one more thought to mention. If anyone or group credits PT results as a manual are they not open to possible liabilities? Now if we reference them as Experimental SML PT Data Results with the mention of "Use at Your Own Risk" that should cover the liability aspect. Now for us in the know we tend to treat it a little differently.
Ed
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Post by AJ on Aug 4, 2019 9:30:57 GMT -5
Just as in reloading manuals, data is a reference point only. Nobody is saying anyone should use load X or Y. There are so many variables now with SML guns just for ignition, it makes it hard to compare apples to apples. What primer did the PT user use, what module was used with the LRMP, was it direct ignition? The barrels we are using in today's guns are probably closer tolerance than what is found on most factory CF guns so that is one thing in our favor. Switching components with ML is just like changing the recipe with CF loads. You change from a Hornady Interlok SP to a Barnes TSX and the output will be different even if the bullet weights are the same. Same with SML. If the trace was done with a crushed rib, the output will be different using a MMP sabot. Another variable that will change things is barrel length. The OBT points are different for a 22" vs a 24" barrel. Not only will a longer barrel give higher velocity, but a overlong long barrel will induce some new pressure issues. The user has to be aware of these things to make the right choices.
I find the PTs a very good reference point. Now the QL software, not so much. I have not had repeatable success using it. I can get much closer using a reloading manual or other pressure traces as starting points. It is like building a wildcat round. I can't tell you how much it irks me when I read some guy builds a new gun with a wildcat chambering then asks on the internet forums for load data. If you have to ask for load data stick to the basic chamberings.
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Post by ET on Aug 4, 2019 10:55:15 GMT -5
Just as in reloading manuals, data is a reference point only. Nobody is saying anyone should use load X or Y. There are so many variables now with SML guns just for ignition, it makes it hard to compare apples to apples. What primer did the PT user use, what module was used with the LRMP, was it direct ignition? The barrels we are using in today's guns are probably closer tolerance than what is found on most factory CF guns so that is one thing in our favor. Switching components with ML is just like changing the recipe with CF loads. You change from a Hornady Interlok SP to a Barnes TSX and the output will be different even if the bullet weights are the same. Same with SML. If the trace was done with a crushed rib, the output will be different using a MMP sabot. Another variable that will change things is barrel length. The OBT points are different for a 22" vs a 24" barrel. Not only will a longer barrel give higher velocity, but a overlong long barrel will induce some new pressure issues. The user has to be aware of these things to make the right choices. I find the PTs a very good reference point. Now the QL software, not so much. I have not had repeatable success using it. I can get much closer using a reloading manual or other pressure traces as starting points. It is like building a wildcat round. I can't tell you how much it irks me when I read some guy builds a new gun with a wildcat chambering then asks on the internet forums for load data. If you have to ask for load data stick to the basic chamberings. AJ You made some excellent points to consider. Thanks for your input on this subject. Ed
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Post by joelmoney on Aug 5, 2019 0:07:11 GMT -5
Very well written AJ
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Post by cuda on Aug 5, 2019 9:05:30 GMT -5
We could just separate the 50s 45s 40s on down he line to make it easier to find the info you need. Good ideas are what we are here for! And YES USE AT YOUR OWN RISK! As you never know what condition someone's gun is in. But we just need to keep in mind of what we are doing when we are loading our guns. As long as we can keep it safe we can mark as a starter load for new shooters. And state what is a normal max load too. GREAT write up!
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