shooting chrony

[bigd]

anybody have one? I just purchased one from WSS, the F1 master version. I haven't used it yet- looking for some opinions please

[bigd]

I did a search and think I got what I needed. I would like to hear any negative comments if there are any out there. Thx.

[209x50]

I have 3 master betas and they work well for me.

[Janitor Pants]

I've got the exact same one and it works great, I found with some of the hotter hand loads you have to place it out farther than you would think to avoid the muzzle blast, but other than that it is really good. If you have a tripod to set it on that will help out a lot.

Also keep in mind that the "traps" you have to shoot over are only about an inch wide and you have to hit both so they are a little bit picky sometimes. Not a problem with a rifle, but with some of the large caliber handguns it can get tricky to have it far enough away to avoid muzzle blast, and still accurately break both beams.

Have fun.

[Tundra Monkey]

Originally Posted by 209x50

I have 3 master betas and they work well for me.

Say that sentence 3 times.....

Sounds like Tree talking about his crew

tm

[209x50]

Originally Posted by Tundra Monkey

Say that sentence 3 times.....

Sounds like Tree talking about his crew

tm

Yeah, my childern never fail to comment on that! LOL

[Grizzly Adams]

Originally Posted by 209x50

I have 3 master betas and they work well for me.

So, why do you have three? I've got the Alpha and it works well for what I need. Definitely an eye opener the first time you use it.
Grizz

[twofifty]

If you have the opportunity, suggest you set up two Chrony and put identical loads over them. You might be surprised at the variations in readings between both chronographs.

For rifle loads over two Chrony units, the velocity readings between the two units varied by well over 100fps. The same rifle load shot over a single Chrony varied by 20 to 50fps. One Chrony consistently gave lower readings, by over 100fps, than the other.

I wonder how well calibrated these instruments are, and what the implications are for those who work up high pressure loads...

209x50, with your three units, perhaps you could do a test and let us know your findings?

[Booner Sniper]

I'm looking at picking one up, what do you guys suggest? I'm thinking of either the F - 1 or the Beta. Any info would be great. Thanks

[twofifty]

The one with the remote display is very convenient and practical.

[209x50]

Originally Posted by Grizzly Adams

So, why do you have three? I've got the Alpha and it works well for what I need. Definitely an eye opener the first time you use it.
Grizz

2 at the muzzle and 1 at 100 yards. The two at the muzzle to get an average, they seldom clock the same speeds but I don't have one that is consistently higher or lower, spread is usually 20 fps or less. The 1 at the 100 yards allows me to generate a BC for the bullet I'm shooting.

[Mulestalker]

I have the same unit,in order to access all the features of the unit like Hi, Lo, Average Dev, Standard Dev, extreme spread, etc you need to buy a "remote" or printer that plugs into the "FU" jack. I made my own with a 3 pole 1/8 stereo jack and a momentary switch so now I can scroll through all the features available,works great. I made 3 off these little guys,let me check to see if I still have them if interested.

[9mikemike]

Originally Posted by Mulestalker

I have the same unit,in order to access all the features of the unit like Hi, Lo, Average Dev, Standard Dev, extreme spread, etc you need to buy a "remote" or printer that plugs into the "FU" jack. I made my own with a 3 pole 1/8 stereo jack and a momentary switch so now I can scroll through all the features available,works great. I made 3 off these little guys,let me check to see if I still have them if interested.

Really, what a thing to call it.

[elkhunter11]

I wonder how well calibrated these instruments are, and what the implications are for those who work up high pressure loads...

Chronographs measure velocity not pressure,and there is no direct comparison of the two that is accurate.Even with identical chamber pressure and barrel length,one gun can consistently produce more velocity than another gun.If you depend on velocity to try and estimate pressure,you need to learn more about reading pressure signs.

[twofifty]

Of course chronos measure velocity, not pressure. But it's reasonable to assert that higher velocities result from higher pressures. I don't believe that anyone here is set up with the instrumentation to directly measure pressure.

So then we look for high pressure indicators -many of which are presented in reloading manuals- such as relative ease of bolt lift or case extraction; burnishing of case head; case head brass flow into bolt head recesses; condition of primer (flattened? deformed? carbon streaked? pierced? protruding?); etc.

A slightly flattened primer may, on its own, indicate nothing out of the ordinary esp. where velocities are in the mid-range or less, but when you've got a couple signs and the velocities are near your manual's max for a given load, it's time to back off a bit.

Certainly, reading pressure signs is not an exact science as many variables come into play. But reading the signs and measuring velocities is a practical way to avoid dangerous pressures.

[elkhunter11]

but when you've got a couple signs and the velocities are near your manual's max for a given load, it's time to back off a bit.

When I see a couple of pressure signs,I back off regardless of whether the velocity is near the velocity in the manual.That brings up another question.I have seven manuals,and the velocities can vary by up to 200fps between manuals for some powder/bullet combinations,so which manual do you use as a velocity reference?

[twofifty]

Since the velocities from your 7 manuals are within 200fps of each other, and chronographs are reputed to be accurate within +/- 4 percent
(which coincidentally is 200fps for a mild 2,500 fps hunting load) I'd say that's pretty close to being the same in the grand scheme of things.

Your decision to back off when two pressure signs show up is a wise one.

However, some signs such as brass migration, are reason enough on their own to back down.

Personally, I don't load to the max as so far the best results came from being in the higher middle of the velocity range. I've seen a few partially flattened primers, a few burnished case bottoms, and a few slightly heavy bolt lifts, but not all at the same time. And I'd guess you do pretty well the same, ending up with safe and accurate loads.

Btw, Elkhunter, I'm a new reloader -have only reloaded 3000rds in one year- but I've been trained and had discussions with very experienced hunters and target shooters whose credentials are impeccable. And I pay attention to and measure what I do. Don't weigh brass or bullets though, nor do I ream primer pockets or case necks - that's for the benchrest crowd as far as I'm concerned.

[elkhunter11]

Btw, Elkhunter, I'm a new reloader -have only reloaded 3000rds in one year- but I've been trained and had discussions with very experienced hunters and target shooters whose credentials are impeccable. And I pay attention to and measure what I do. Don't weigh brass or bullets though, nor do I ream primer pockets or case necks - that's for the benchrest crowd as far as I'm concerned.

I am not a new reloader,I have been at it for over 30 years,loading anywhere from a few hundred rounds to a few thousand rounds per year,for a total that would exceed 20,000 rounds.In all that time,I have relied on two pressure signs more than any other,those being primer pocket expansion,and measuring case web expansion,both of which are closely related.I find that these two indicators occur much sooner than other pressure signs such as brass extrusion,or hard bolt lift,which only appear at very high chamber pressures.
Good teaching is definitely a good thing,but in my opinion,nothing beats actual experience dealing with many different cartridges,bullets,powders,primers and cases.Too many people trust loading manual data as always being right for their gun,without bothering to learn about the variables,that prevent that from being possible.

[twofifty]

Great, I get to learn something new:
pls. tell me about measuring case web expansion and primer pocket expansion.
How do you decide what is significant and what normally occurs when a round is fired?

[elkhunter11]

pls. tell me about measuring case web expansion and primer pocket expansion.
How do you decide what is significant and what normally occurs when a round is fired?

Once I decide that a load is to be considered for a final hunting,or target load,I load three new cases with the load and fire them.I reload and fire those same three cases with that same load five times,and if the primer pockets are still tight when I insert new primers after five firings,no significant expansion has taken place,and I consider the load safe to use in my gun.

As far as measuring case web expansion,I use a micrometer or vernier that measures to .0001".I measure each case at the belt diameter for belted cases,or at the rear most part of the web,ahead of the groove for non belted cases, before firing(new cases) and after firing.If there is no measurable difference,I assume the load to be safe.As the powder charge is increased slightly,at some point,you will start to see some slight expansion.When the expansion reaches .0002" or .0003",I stop increasing the powder charge.This seems to be the range that I see when comparing most factory loads before and after firing,hence my reason for picking this range.However,I have seen some factory 257 Weatherby loads expand .002" at the belt after a single firing,which to me indicates way too much pressure,or very soft brass.

[twofifty]

Very methodical and logical.
Thanks for that.

When you ".... decide that a load is to be considered for a final hunting,or target load", have you worked up loads to that decision point, and then apply this rigorous method to determine that the brass will contain the new load's pressure for the expected lifespan of that brass, i.e. 5 reloads in the example given?

[elkhunter11]

When you ".... decide that a load is to be considered for a final hunting,or target load", have you worked up loads to that decision point, and then apply this rigorous method to determine that the brass will contain the new load's pressure for the expected lifespan of that brass, i.e. 5 reloads in the example given?

When I have reached that point,I have already worked up the load while measuring case web expansion.I have settled on a powder charge,and the seating depth,and my last step before accepting the load is to do the primer pocket test.

[twofifty]

Thanks again.