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Topics - bikemutt

1
General Discussion / To harmonize, or resonate
I used to tell folks that, if reincarnation really happens, I want to come back as my wife's dog, really though, I want to come back as a machinist, who's married to my wife of course, and the dog is still in play :)

Since none of the above is really going to happen, I'm on a quest for a more perfect, affordable drill press. After talking to a couple guys who have real jobs, working for real companies that make real things for the likes of the military, the net result distilled down to a 3-phase motor with a variable frequency drive, or VFD as it's generally known.

What in the heck does this have to do with guns? Hang in a bit, I'll connect my crazy dots in a bit.

What I'm learning is that just about everything has certain frequencies where they ring like a bell. It never occurred to me that a heavy machine like a drill press could vibrate to a degree that calls attention to itself or, more importantly, could trigger vibrations further down the food chain, as in X and Y axis instrumentation.

What I discovered once the VFD and 3-phase motor were in place is, I now could dial in motor speeds that avoid the resonant frequencies of the entire machine. I may be overstating the case but, all I really want is a silent, smooth, powerful drill chuck, not a vibratory disco dance floor  :o

Which made me think about barrel tuners, something I know little to nothing about.  One more thing to think about at 3:00 am :)





5
General Discussion / Switch-barrel rifle thoughts
To say that I'm attracted to mousetraps might be a understatement, lol.

I've always been fascinated with switch-barrel rifles; those where it's easy to switch barrels within the same bolt face, easy to switch bolts when required, and one that uses familial magazines. The most obvious benefit, to me, is the receiver doesn't change. This dials out fitment issues, the trigger is the same, the scope needs a simple dope sheet to get it more-or-less on track with a minimal amount of fine tuning. Cost savings may be substantial since barrels are generally cheaper than buying one rifle in each caliber.

I wonder though, are switch-barrel rifles inherently accuracy-compromised?

Figured I'd throw it out here to see what you guys think. 
6
General Discussion / Does a Lead Sled have a place in load development?
This is an honest question, not meant to stir up trouble.

From a strictly load development standpoint, are there merits, and pitfalls employing a device like a Caldwell Lead Sled in order to make load development more about the equipment, and less about the shooter?

Some of the terms and pearls of wisdom I've seen on the forum include: "3-shot groups are more about the rifle, 5-shot groups are more about the shooter", "...with proper bench manners...", etc.

Considering the extremes, an inexperienced shooter paired with an inherently accurate rifle will most likely produce similar results on the target as an experienced shooter paired with an inherently inaccurate rifle. Maybe.

Anyway, I have a Lead Sled sitting in a box, never been opened. Is it Pandora's box, or a useful tool?

 
7
Reloading / Reloder TS 15s powder
Just read a report on Reloder TS 15s which looks promising for 6.5 Creedmoor.

Quote
...is an extruded, double-base powder physically similar to Reloder 16. Its chemical composition includes a small percentage of nitroglycerin for extra energy and also a decoppering agent to minimize barrel fouling. The TS prefix stands for "temperature stable"...

What got me to put on my cheaters and read the accuracy chart more carefully is the performance of two loads in a rifle near and dear to my heart; a Browning X-bolt Target 28" barrel.

Speer 140 gr Gold Dot JSP over 37.5 gr powder managed 2638 fps with an average 100 yd 5-shot group size of 0.74".

Federal 140 gr Fusion JSP over 37.0 gr managed 2650 fps into 0.93".

Those speeds aren't great for that rifle but, the author did start on the low side owing to the newness of the powder.

Of course, none of this matters if the powder is unobtanium but, if it is available, having another alternative to the well-known staples can't be a bad thing :).  
8
Reloading / Autotrickler V4
I said I wasn't going to order one, and I really meant it. I reserved one back in March, but I was not going to order one, no siree, not I.

Then I folded like a cheap tent last week and ordered one anyway :(

Should see it mid November or so according to the latest report from Adam.

9
Reloading / Force Gage availability
Starting a new thread here so we can talk about the Force Gage tool rather than my experiments :)

I've decided not to try and monetize this effort; I retired from my work life for a reason; not looking for a new job. My desire is to make the tool available to anyone here who would like to have it.

Here are some things to consider:

Some hardware is required, a cost that, for the most part, cannot be avoided. The current parts price list I have built up, is $346.

A K&M press lists for $136 plus s&h. I have no interest in working on adapting to another press, but anyone is free do so.

The press will need one small modification. The top of the tower will need to be tapped 1/4-20, no need to drill, the holes are through-holes that run the full length of the tower, their diameter is correct for a 1/4-20 tap. Using 99% alcohol as a lubricant, takes 10 minutes or so to tap both holes. If I can do this, well, you know the rest of the story. Tapping these two holes in no way affects the normal use of the press.

Since it's fitted to an arbor press, that pretty much means a commitment to inline seating dies.

A decent PC is required. It doesn't have to be a raging fast, expensive rig. I run the software on an Intel Mobile-M processor which is no speed demon. Two available USB ports, or a USB hub required.

Microsoft Excel is really nice to have; it will work without Excel but the ability to save information and post-process it, will be lost. I could probably fix that but for now, it's probably cheaper to buy an older version of Excel on eBay.

The load cell MUST be calibrated. This is easy to do if you have a decent quality postal scale available. I have a 75lb capacity postal scale that works great. All that's needed to perform the calibration is a way to apply a constant force to the load cell as shown on the scale display, record the voltage reading for that force, repeat for 6-10 different forces, type those into a spreadsheet which crunches out a pair of coefficients, enter those into Force Gage one time, done. It sounds harder than it really is. I use a Harbor Freight $10 deep C-clamp to provide the squish force.

There are a couple of aluminum adapters needed to mount load cell and position sensors. I can either make those, or tell you how to. A piece of round stock and flat stock needed. Or, maybe you see a better, easier way to mount the sensors, even though I've spent hours trying to exceed my clever limits, someone else may see something I overlooked.

What's left is the software. There are three pieces right now; Force Gage (the tool), Force Gage Viewer for post-processing, and load cell calibration which simplifies the calibration process. Even though I'm happy to explain to anyone how make this work, it won't save time or money since mine is free, lol.

So there it is, figure about $400 and some shop time if you already have a K&M arbor press and inline dies, and a PC of course :)

10
Reloading / Bullet Seating Force Gage ruminations
I've been buried in a lot of non-gun stuff for what seems like forever but, I've not lost sight of instrumenting the bullet seating phase we all deal with.

From the last time I posted, progress has been made.

Measuring force and distance was previously limited to about 50 samples per second which is not bad but, considering the entire seating operation takes about 1 second, the sample rate limit was an incentive to stretch the operation. The sensors, and interfaces I'm using now have a sample rate of around 120 per second. The result is more granular tracking of the seating stroke without trying hard to time-meter the stoke, and the cost increase for the improved performance is less than a box of factory hunting rounds.

It's either been said by someone famous, or maybe I made it up but, the best way to improve software is to force the programmer to use it; I've used it, a lot. I feel the program, once the important settings are understood, is recording and presenting accurate information.

Anyway, figured I'd share a reloading session from earlier today where I tried to make the best ammo I could, and recorded it.

5x fired 6.5 Creedmoor Lapua brass, body sized and bumped 0.002", neck sized with a Lee collet die.

Necks 2x treated with Neolube, first application allowed to dry, then a second application.

Hornady 140 gr BTHP bullets seated 33 OTL.

LE Wilson micrometer seating die with an instrumented K&M Precision arbor press.

Here's a screenshot of the seating curves:



The X-axis shows ticks, each tick represents 0.01 millimeters or about four ten thousands of an inch. The total seating distance is about 0.27". The Y-axis shows force in pounds.

This group of 20 seatings doesn't surprise me with it's consistency; that's what two applications of a neck lubricant seems to do in my limited experience. The first phase, up to about 560 ticks covers the insertion of the bullet into the neck and, patting myself on the back, indicates the hand loader got his neck tension down quite well, dissention and disagreements are welcomed of course :).

The second phase between 560 and 960 ticks shows a divergence of seating forces which spans about 10lbs. I don't know what that means but, I can say with certainty, not one of these strokes called attention to itself, I simply felt no difference from 1 through 20.

The force trend after 960 ticks seems to dip slightly, then the brick wall hits with the die being fully compressed. I don't know how much stock I put in the last, tiny bit of movement and force, it's an infinitesimal amount of movement with a dramatic increase in force. Do some seatings really put up a fight at the ragged end or, are we at the resolution limits of the instrument? I'm inclined to believe the latter until experience indicates otherwise.

I'm going to shoot these, record the metrics and the target which I'll share. I've marked the cartridges in order to directly relate them to their seating force curve. Fun stuff!

 
11
Reloading / Compressed load question
Asking only because I've never run into the possibility of a compressed load since I usually seat longer than recommended COL.

I take a fired case with it's spent primer in place, add the charge weight of powder I normally use, then gently drop a bullet into the mouth. If the bullet rests deeper in the case than I plan to load actual rounds for, is it safe to assume I won't have compressed loads?

Thanks
12
Reloading / Lee neck sizing collet die redux
Being curious about what Lee means when they recommend pushing the handle a minimum of 25lbs, I ran a quick experiment this morning.

Using a Forster CoAx press with a Forster stubby handle, I set a 200kg (440lb) capacity load cell on the shell plate and zeroed it. I let the handle gently down onto the load cell; 28lbs, that's without applying any force to the arm, just gravity at work. Using a Lyman trigger gage attached to ball of the stubby, I pulled to 11lbs 10oz (the gage does not read above 12lbs), the load cell reports over 400lbs of force  :o

So, I'm still not sure what the 25lb suggested force Lee recommends but, I'm pretty sure they are not referring to the ram force on the die  :D.

If Lee means applying 25lbs to the press arm, that needs to qualified according to the mechanical advantage offered by the press itself. If approximately 12lbs of force on the stubby lever of a CoAx can generate a compressive force on the ram in excess of 400lbs, that will be very different with the standard length arm.

Anyway, we all have our techniques for using the Lee collet dies, not trying to change my mind, or anyone else's, just curious is all.

 
13
Reloading / Seating depth update thoughts
Where we'd left off last time,  I'd increased powder charge from 41.3gr to 41.7gr H4350. 140gr Hornady BTHP bullets in my X-bolt seated .030 OTL looked encouraging.

Today I ran up from .030 to .035 in 0.001 increments, I think I found a seating node but, it seems quite narrow.

It was fairly windy at the range as well as plenty of mirage, gotta have at least a few excuses, lol.

I'm at a loss on the .032 target other than there was one extra fast round; 2851 fps when the rifle was shooting right at 2820 on average. In any event, it looks like a divergence before a convergence but, it is what it is.

Things look pretty good at .033 and .034 in terms of group size, then a divergence again at .035.

I'm not sure if I give what may be a narrow node another try at this speed, or drop 100 fps where the rifle also shoots well and look for a wider seating node. What do you guys think?

14
Reloading / Powder lot change
July is coming to an end, time to use up my monthly dumb question allowance, lol.

What do you guys do if you're faced with changing powder lots halfway or so into a loading session?

I know, proper planning would prevent this, I slipped up.

15
Angie's List / Brownells deserves a shout out
I decided I'd try returning a couple items to Brownells, figured I might meet with some resistance, or at least have to spend time on the phone begging.

Not so; all I had to do is login to their website, click on my order, return. I was emailed a packing slip and a label. Boxed up the parts, enclosed the packing slip, stuck the label on the box and handed it to the letter carrier. A week later the items were credited to my card. No charge for return shipping.

Brownells will continue to enjoy my business!