Tuesday, May 29, 2007

The tale of two cases

It was the best of brass. It was the worst of brass.

My Remington 700PSS in 308 will shoot scary-accurate groups when fed my personally developed handloads. These are 168gr Sierra BTHP bullets, seated to an OAL of exactly 2.815" over exactly 42.5gr of IMR 4064 powder in BHA match cases primed with CCI 200 primers.

However, when I build rounds using this same recipe but substituting the BHA cases for something else, the rifle will not group. I recently tried an experiment when I built up a batch using the recipe above, and another batch using the same recipe but substituting Federal Gold medal match brass instead of the BHA cases.



I then fired a five round group of each, from 100 yds thru a Chrony chronograph.

The target on the left is the FC load and the target on the right is the BHA load. I confirmed that the loads built with BHA brass are still deadly consistent (that's about 0.3" center-to-center), but those built with FC brass don't group all the well.

The chronograph tells the difference. The BHA loads clocked in at 2571.1+-21.4 fps, while the FC loads clocked in at 2643.3+-6.4 fps. So even though the velocity spread of the FC loads was smaller than the BHA spread, the BHA loads group much better. This says more about the rifle's barrel than the load; apparently the 700PSS really likes the 168gr Sierra bullets to be going at about 2550 fps.

So, what explains the almost 5% velocity difference between the BHA loads and the FC loads? Measuring the case volume (grains of water) showed that the BHA brass has a volume of 56.6 grs of water, while the FC brass has a, smaller, volume of 54.3 grs of water, a 4.2% difference.

So, there you have it: a 4.2% decrease in case volume results in enough increase in chamber pressure to cause a 5% difference in velocity, and a 5% change in bullet velocity can really throw off a finicky rifle.

MORAL OF THE STORY: Don't substitute components when handloading.
CORROLLARY: If you must substitute, start over with the workup.

Saturday, May 19, 2007

Trigger job for your Ruger GP100

Ruger GP100s are reliable revolvers that are a lot of fun to shoot. Unfortunately, out of the box, the trigger pull is heavy and the trigger can be "stagy" and rough.




However, with a little elbow grease, a set of miniature files ($26.45 from Brownells), a ceramic stone ($29.95 from Brownells) and a set of Wolff Gunsprings springs ($10.50 for a shooters pack) one can do-it-yourself, acquire some knowledge and tools for future trigger jobs.

After taking off the stock, the first step is to remove the hammer strut and hammer spring. There is a hole at the base of the hammer strut. Cock the hammer back and stick a toothpick into this hole, all the way through the hole.


Now, release the hammer by gently squeezing the trigger while holding the hammer, and letting it gently fall. The toothpick will hold back the hammer spring and the spring and hammer strut can now be removed as a module.

The hammer is free to move without spring pressure. Now, pull the hammer back and gently drive out the hammer pin using a chopstick or other non-marring rod of similar diameter. The hammer can be removed out the back of the revolver.



The next step is to remove the trigger group. Using a chopstick (or other non-marring rod of similar diameter) push on the detente pin on the inside of the revolver grip.



While pushing on this pin, with the other hand pull down on the trigger guard. Once the detente pin is free of the hole in the grip frame, you should be able to cantilever the whole trigger group down and forward.



At this point, the trigger sear and hammer engagement surfaces should be visible. The goal of polishing these surfaces with a stone is to ensure the removal of all manufacturing burrs and blemishes and thus guaranteeing smooth movement of metal surfaces over one another. When polishing with a stone, do so slowly taking off a little metal at a time until the desired surface is achieved. It's preferable to apply pressure on the stone only when moving in the direction towards that of an edge. Never stone an edge itself.

First, stone the trigger sear engagement surface.



Next, stone the hammer engagement surfaces.



At this point, you should check the hand slot and the cylinder lock slots, respectively, for manufacturing burrs. Burrs in either of these slots will result in drag and catching of the hand and/or cylinder lock respectively.

What's the hand slot you ask? The hand is the piece that rotates the cylinder of the revolver and it sticks through the hand slot in the back of the revolver.



Similarly, the cylinder lock is a piece that pokes up through the cylinder lock slot in the bottom of the revolver. It locks the cylinder it place so it doesn't move while firing.



With both slots, check that the hand and cylinder lock, respectively, move freely and easily. If not, very carefully file the inside of the slots with a miniature square file, removing any burrs or blemishes as necessary. Be very careful to remove only a small amount of material at a time, and only as much as is necessary to achieve free movement.

Two springs should be replaced to lighten the trigger pull; the trigger return spring and the hammer spring.

Remember the detente pin you pushed in to remove the separate the trigger group from the frame? The trigger return spring is right behind it. The weight of this spring, singularly, determines single-action pull weight.



The hammer spring is being held back by the toothpick on the hammer strut. Carefully separate the hammer strut and hammer spring by extracting the toothpick. Do this someplace without a lot of dark nooks and crannies, in case you have to chase the spring. :-) The weight of the hammer spring is the primary contributing factor to the double action pull weight, and secondarily to the single action pull weight.



For the trigger return spring and hammer spring, I recommend 10 lbs and 12 lbs, respectively, if you buy the shooter's pack mentioned above, you can experiment.

Sunday, May 13, 2007

al Qaeda affiliated cell broken up in Saratoga CA

PRESS RELEASE

al Qaeda affiliated cell broken up in Saratoga CA

For immediate release (AP [Amateur Press] Saratoga, CA)

Saratoga, CA—April 17th, 2007

In the early hours of the morning of April 17th, 2007, agents from the Department of Homeowner Security confirmed that weeks of quiet counter-insurgency work had finally paid off with the death of two members of an al Qaeda affiliated cell working in Saratoga CA. The cell, a member of the little known group calling itself RAT (arabic for “Resistance Movement for Allah"), was loosely affiliation with al Qaeda, says agent Flix Estrada of DHS who was present on the scene.

Their capture and death is the culimnation of weeks of careful counter-insurgency operations. “We used what we learned from operations in Iraq and used it against the terrs!” says agent Flix Estrada. “We devised several SASDs [Self-Activating Snapping devices] charged with almond butter, since the terrs can’t resist almond butter. Once their little grabby paws touched the trigger mechanism, the trap would be sprung, crushing the prey. If they weren’t dead by the time we found them, a quick shot from a silenced .17 calibre pistol to the head would dispatch them to the land of 72 virgins!”

On their persons, agents found an assortment of WMDs. Says agent Estrada, “We found HE warheads, still in their blue shell, and what looked like a partially constructed nuclear device, similar in shape to a “Fat Boy” bomb dropped on Nagasaki in 1945. These guys were well on their way to achieving their final goal!”

Operations are still ongoing, to clear out the remaining RAT cells, but agent Estrada is confident that the primary cell is disrupted and on the run. After weeks of nerve wracking attention, even Estrada’s dog is calming down.



Remington 700 Sendero workup, part 2

Following on the load workup around a 168gr HPBT, I was at the range yesterday working up a load around a 200gr Sierra HPBT bullet. Damn, this gun just goeeessss! The following pic is of a 100yd 4 shot group (OK, 5 shot group but I fumbled the first shot so badly I'm embarrased to admit it was part of the same group -- you can just see the edge of the hole at the 10 o'clock position on the black circle); 72.5gr of Re 22 for a speed of 2949+-14.1fps.


Saturday, May 12, 2007

Ruger Security Six Range Report, part 2

In part 1 I talked about first impressions of the Ruger Security Six with 2" barrel.

Replaced the tiny factory stocks with a Hogue rubber mono-pod. This allows a much tighter grip and hence the gun doesn't shift around in the hand between shots.



After adjusting the sights so that POI is now POA, I tried a load comprised of Alliant 2400 powder instead of Winchester 296. Here's a target shot at 15 yds, offhanded, with Remington 125gr JHP-GS over 17.2gr of Alliant 2400.



Quite a difference. I think this gun actually likes light bullets.

Friday, May 11, 2007

Reincarnation

Do I believe in reincarnation? Yes, I do. I believe in the immortal soul. I believe in Karmic ranking. I have sinned in this life and hence, I believe that in my next life I will come back as a Push-Up bra.

When disk drives go bad, or Exorcising the spinning demon

In my chosen profession, I come into contact with disk drives that go bad. They corrupt data, they spew forth foulness up their interfaces, they cause mayhem and downtime. With the aid of my assistant and several tools of exorcism, I attempted to remove the demon from the mortal souls of several individuals thus afflicted. The following pictures show the results.

First, the tools of the trade—the quarter and the round, and the probe.




And here is the first individual, from the front and from the back. That exorcism was messy and involved.





The second individual was more complacent and the evil was struck right thru the evil eye—from the front and from the back.


Wednesday, May 9, 2007

Ruger Security Six Range Report

Picked up a blued Ruger Security Six (SS) with 2” barrel recently. Why? Because I like 357s and I like snubbies.

Ruger stopped production of the SS sometime in the 80’s and replaced it with the GP100 and SP101. Sizewise, it’s almost identical to the GP100. The front sight on the GP100 fits in a dovetail whereas on the SS the base of the front sight is part of the barrel but the blade is replaceable. Furthermore, the GP100 lug extends all the way to the end of the muzzle, whereas the lug on the SS ends just past the ejector rod. Here’s a picture of the SS alongside a GP100 and SP101, for size comparison.



And here’s a closeup.



Whenever I buy a revolver I wish to work it over to achieve a smooth and light trigger pull. The first part proved to be a bit of a challenge with the Security Six. Unlike on the GP100 and SP101 (where it’s part of the trigger group) the cylinder lock/latch on the SS is a seperate, cast piece fitting into the underside of the receiver, pivoting in a recess of the receiver and sprung by the cylinder crane pivot. See here.



The problem is that since it’s a cast piece, the bearing surfaces are not necessarily polished. The lock is moved down by downward pressure of a hook on the leading edge of the trigger assembly, and though the trigger hook can be polished fairly easily, the lock surface can’t be easily polished because of the angles involved. A 1/4” diameter felt pad and jeweler’s rouge finally did the trick. Here’s a pic of the bearing surfaces.



Finally, a snip of one loop off the hammer spring lightened the trigger pull to where I like it.

It followed me to the range on Saturday, along with the GP100 and SP101 for comparison, to try out some accuracy experiments using three loads. I’d forgotten to bring my tiny screwdrivers so the gun was shooting to the right and I couldn’t adjust the POI. No big deal.

I tried three loads, all fired from 15yds, offhanded, shooting one-handed.

(1) Ranier 158g RN over 15.2gr of Win 296


(2) Winchester 158g JHPP over 15.2gr of Win 296


(3) Remington 125gr JHP-GS over 17.4gr of Win 296


My overall impression is that the gun is pleasant to shoot, and reasonably accurate. Considering the short barrel, achieving headsized groups single handed is a snap, and as typical of shorties, heavier bullets group better than lighter bullets. The tiny stock combined with the weight of the gun, however, allows the gun the move quite a bit between shots when shooting one-handed, requiring frequent grip readjustment. A Hogue rubber finger-groove mono-grip would help here.

The speech I would like Bush to make

A potential presidential speech writer writes the following speech for Bush. Too weak, I say. Here's the speech I would like to see Bush make.

“I’ve been accused of lying, but you morons don’t even know the half of it. All this talk about building bases in Iraq, and the war not being about bringing democracy to Iraq .... OK .... you’re right. The war wasn’t about bringing democracy to Iraq, because you can’t force democracy on a people who wouldn’t know it if it bit them on the ass. The goal of the war was two-fold:

  1. remove a heinous dictator who threatened trade in the middle east, and
  2. establish a permanent US military presence in the middle east.

The latter point needs clarification because you fucking morons don’t get it. The US didn’t achieve its prosperity and power by good deeds and wishful thinking. We established it by guaranteeing free trade, for ourselves and for our trading partners. The terrorists in the middle east cannot be allowed to succeed in what they want to achieve; a pan-Islamist state that is intolerant of western beliefs and trade. Only military might can counter this threat and a military presence in proximity of this threat is essential.

Clear enough?

No further questions. I will now give the orders for our military to do what they need to do to succeed in Iraq. No more “Mr. Nice Guy”, silly “rules of engagement”, and ham-stringing by politicians.

And all you twits who think I want to be remembered as a great “war president”, like Lincoln and FDR, can kiss my hairy beanbag. I want to achieve nothing more than what Jefferson achieved when he took on the Barbary states and their pirates: I’m calling their bluff and will destroy them ... to guarantee free trade and US prosperity. Good night!”

Here’s to all the Elvis fans

Enjoy ..... A Springfield Armory Loaded with custom carved scrimshaw grips by Sydney Ryan.

Remington 700 Sendero SF-II in 300 Win Mag

Today, I took my Sendero up to the range for a load workup and accuracy exercise. Last week I broke in the barrel with 70 rounds.

The load I was working up was a Sierra 168gr HPBT bullet over Re 22 powder in FC match cases. First a couple of pics of the gun.





The glass is a Leupold VX-3 3.5x10x40mm, the base is a NightForce 1-piece 20MOA.

For the weight (about 7lbs) the gun is quite comfortable to shoot even with hot commercial loads. The factory trigger, though a little heavy (5 lbs) breaks crisply and cleanly.

Yeah, yeah ... but is it accurate? Is it ever. I worked up weights from 75.0gr to 79.0gr, with a 0.5gr delta. Surprisingly, the two extremes were the most consist velocity-wise and accuracy wise. Here’s some target pics, shot at 100yds.


75.0gr Re 22 (3028+-29.8fps)


79.0gr Re 22 (3274+-9.6fps)

I think we have a winner. The horizontal spread (in the latter) can be explained by wind (it was quite gusty today).