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Mike Pal
Why would I spend $130 plus dollars for possible better ignition when I’ve already accomplished that with a onetime modification?
And no interruption to shooting to load modules and never having to replace them for any reason.
You’d be surprised how fast I can clean a BP with a few assembled tools kept handy in a kit, chuckle.
No problem whatsoever. ;)
Attachment 28695
Ed
The 50 SML can have a good kick to her when fired. You can reduce this kick some with a recoil reducer installed, a better butt pad installed and wearing a PAST shoulder pad. But this stout recoil still affects accuracy at the range especially using synthetic stocks because of their flex property. What was found to be helpful was to place the front rest bag as close as possible to the recoil lug as comfortably as you could handle.
When shooting a kicker my shooting technique differs with the amount of firmness I apply to shoulder fit. I also try to firm up my neck muscles so that when my shoulder moves back my head follows as well. So far no scope eye, chuckle. Having a scope with longer eye relief helps in this situation.
My preferred method is allowing the fore-stock to free recoil. No contact or interference to influence its response from recoil. With my shooting stick my left hand holds the stick and does not contact the fore-stock.
This is not a set in stone method but one that works for me handling heavy recoiling SML’s or rifles.
With heavy recoiling firearms flinching can easily set in and spoil your accuracy. It’s natural for the mind to instruct the body’s reaction to protect itself. Once flinching sets in you will have a hard time breaking that habit. Been there and done that.
There are still a few variables that can affect accuracy but to address one at a time is my preferred method.
Ed
Quote:
Originally Posted by MikePal
The VF's look interesting to me. I sometimes wonder how far the bullet/sabot combo is pushed before charge is actually ignited with a 209.
You would think that the pressure from a magnum primer would surely be enough to push it past the initial inertia of the load and remove some pressure off your powder.
Wouldn't that affect the overall pressure, velocity and accuracy ???
Maybe the initial pressure on a sabot gas cup would seal it quicker allowing the pressures to build higher ??
I’m not going to jump directly into a hypothesis being formed but will add a variable to consider.
Load resistance can alter the final peak pressure and resulting velocity. With a given load of 250gr bullet using 43gr of 4759 in a 50cal using 10lbs and 40 lbs of load resistance the greater load resistance will produce slightly higher peak pressure and velocity.
The PT shows pressure buildup occurring under .1 mil-secs. and completes the cycle of bullet exiting the bore under 2 mil-secs.
The underlying question is how much pressure from thermal energy gets into the bore before powder ignites building its own pressure with a time frame under .1 mil-secs.?
With Cecil’s theory of bullet movement he removes the ignition factor and shows only how much pressure a primer generates for bullet movement where all pressure from primer is allowed to affect bullet movement through its own cycle. This does show the strength of the primer capabilities. Just something to keep in mind when doing your analyzes.
Ed
Not sure Ed but I received my 700 custom smokeless from PR bullet last week that utilizes a 6mm case cut down. Supposed to improve seal. Guess we will see how it works.
Big Jack
I look forward to hearing your results as I have followed others using modules or actual brass casings to house the LRP. I agree that sealing will help for an improvement of focusing more thermal energy to powder.
Here precise fit is important for that seal. I take it not any 6mm brass casing can be employed because of slight different web dimensions so your supply will probably have to come from PR bullets. Some have noted flame cutting over time so a careful watch of inside the brass and possibly the head contact on the BP should be monitored.
I look forward to reading your results especially with temp range and different powders.
Any noted wear observations would also be appreciated.
Have to ask if this is a 50 or 45 as 45’s are becoming more popular. This will be the next generation of SML IMO.
Hope your expectations are met with the new custom SML and have a lot of fun with it.
Ed
I bought an extra pac of the small rifle primer VF adapters for my 209 plugs.....I see he sells the 6 mm adapters for $2 ea (x10 for $20)....throw them in with some bullets and save a bit on the s/h :)Quote:
Originally Posted by Big Jack
Because of the interest in learning more about internal ballistics this was also a prompt to get a PT unit. As mentioned it can show more than peak pressure. Some of the functions I haven’t mentioned because they would probably not be of interest to most. The one function I enjoy using is monitoring different points of the pressure curve. This is done with a moveable cursor that can move as low as .02-milliseconds.
A while back I began monitoring my experimental powder load of the new 4759 while trying to apply it to a 200gr bullet. What I did see was an erratic pressure decay that I did not yet experience. I was surprised to see where pressure instead of decaying was trying to slightly climb again and measured about 1,200PSI increase at one location.
Attachment 28750
So what does this suggest to you about this particular powder burn?
Ed
Well I’ve done enough talking about the 10ML-II and smokeless powders for now.
My choice for a duplex booster has been made and will just leave a picture of the powder for anyone to contemplate my reasoning. This powder choice should also yield a lighter single powder load with a smaller bullet.
What hasn’t been mentioned is how to tailor a duplex load and remain in safe pressure limits.
How to monitor and adjust for temp sensitivity.
Maintaining a simple log book is an asset and good practice.
No sense in getting into the above mention until I have some test samples to review in the spring.
Attachment 28771
Ed