jwhittin

This is what is meant by follow through.

I don't shoot 9mm but people I've spoken to are typically in the 8 to 12 fps range. It depends on your components, equipment, and your reloading process and any changes in any of those areas can change your STD. For 40 Maj, my STD is about 15 to 20 fps. I've used the same load, components, and press/process for several years so I haven't see much change.

That's the reason your results are not consistent. With only 3 rounds there is a high statistical uncertainty in the measurements. Use 8 rounds and know your standard deviation (STD). Add 2 to 3 times your standard deviation to the minimum required velocity to make PF. That is your desired average load velocity. That gives you a high degree of confidence of passing PF.

"The PF readings were inconsistent (I made sure that all loads are equal in regards to specs)" How are you measuring your average velocity? How many rounds and what is the Standard Deviation?

The spherical ring allows the barrel to move in and out of lockup with a very tight bushing tolerance. The rings are selected to be no more than .001" larger than the barrel diameter. That results in very little muzzle movement in any direction. I think the standard bushing clearance is 2 or 3 times more and could be worse if not properly fit. I will calculate the minimum vertical value and post it. IF a standard bushing is custom fit, I suspect the horizontal value is about the same as the ring. But due to the geometry, clearance in the vertical direction must be larger than the ringed bushing. It will be interesting to see how much larger.

Cross posting as I think this is a better location. You

Great info! Keep it coming. Does anyone know how to cross post (is that a BE feature)? I think people might look in Gear & Accessories for this type of info.

Never heard of this gadget. Want to learn more. Who makes it?

Not 100%, just a high probability. As I have mentioned, using more than 8 to 10 rounds to measure is a waste. Try it. Record STD and Avg Velocity using 10 and 20 rounds. No difference down to one decimal point. With your approach you end up much hotter than needed. This is a kin to using the ES instead of the STD. So you could end up at 4, 5, or even 6 times the STD. At 3STD you are already at 97%. Just trying to save you some ammo and make you a better shooter ?

There is no way to know using the PF chrono results. Maybe the powder manufacturer knows the sensitivity or you could test your ammo at different temps. Then load for worse case conditions.

Braxton is on the right track. You can't get consistent velocity results using only 3 samples. What you need to pay attention to is your measured standard deviation. But you only need 8 samples to get a valid estimate. Then add at least 2 times your STD to the velocity needed to make PF. This gives you your desired avg load velocity. This ensures at least a 90% chance of passing the chrono check in the first 3 rounds. 2.5*STD gives you 95%, 3*STD corresponds to 97%. So if you STD is say 15fps, you want your average velocity to be at least 718+30=748fps measured using 8 rounds. Make sense?

OP - How were these two measurements taken? We're both results of the match chono? Did you check one yourself? If so how many rounds?

I'm getting to the point where I need hearing aids. Are there any hearing aids that could also be used as hearing protection at the range? Or can the typically hearing protection devices also serve as every day hearing aids?

Great idea. And inexpensive too.

You can incorporate one step with any drill at the indoor range.

My homeboy Smokey.

I have experienced this. we had to get it about a foot away. It wasn't easy to do.

Dawson bases with Gram Engineering followers and springs is another good option.

The product makes sense to me and I installed one on a limited gun. I have about 10k round on it with no problems. No barrel movement and very smooth. Bushing failure could be due to fitting. I've had a conventional bushing crack on a Sig 1911. Doesn't sound like there is a problem with the Briley bushing.

DAA holster and belt with Safari mag holders.

I would also say about 30 to 60fps higher just based on some of my own measurements.

All the ones mentioned make high quality ignition system. There is no problem dry firing. They should last 40k or more before they need any attention.

I run 180gn Extreme plated RNFP over 4.3 gns of Titegroup with an OAL of 1.125".

Did you check with your gunsmith? Some smiths wont go below 3.5 or 4 lbs.

I struggled with progressive lens for a long time. Tried single vision lens set for front sight in both eyes but distance vision was a blur. Switch out non dominant eye with single vision distance len and now I can see both my front sight and distance clearly. Find a shop that will let you bring your firearm in to optimize you perscription.