April 6th, 2014

NSSF Takes Over Rimfire Challenge Program

The National Shooting Sports Foundation (NSSF) has taken over the Ruger Rimfire Challenge program. Now called the NSSF Rimfire Challenge, the program retains the format that has made it so popular. This remains a two-gun timed competition with rimfire rifles and pistols. Shooters engage steel targets at relatively close distances. The matches are for young and old alike, all skill levels, with mentoring by experienced shooters. The emphasis is on fun and safety.

NSSF Rimfire Challenge

The use of .22 caliber pistols, revolvers and rifles make the Rimfire Challenge more affordable than most centerfire matches. “The affordability of this program is something that participants really like and keeps them coming back,” said Zach Snow, NSSF’s Manager of Shooting Promotions. “Event fees are affordable as well.”

For participants, NSSF Rimfire Challenge offers categories for everyone — Open and Limited Divisions, plus Special Recognition competitions. To learn more about on program equipment, rules, courses of fire, scheduled matches and the first NSSF Rimfire World Championship, visit NSSF.org/Rimfire.

    NSSF Rimfire Challenge Basics

  • This is a two-gun event so you need a rifle and a handgun (which can be either a semi-auto pistol or revolver).
  • Bolt-action rifles and lever-action rifles are allowed, but self-loading (semi-auto) rifles are most popular because they can shoot quickly.
  • It is suggested that your firearms hold at least ten rounds each, as there is no reloading allowed during the actually stages.
  • It is a good idea to have five (5) magazines per gun (5 each for rifle and pistol). That way you don’t have to reload between stages. If you have a 10-shot revolver, you can reload manually, or use speed loaders.
  • At Rimfire Challenge Matches, each competitor get five (5) runs through each target stage.
  • Eye and ear protection is required on the range at all times. This is true for spectators as well as competitors.

NSSF Rimfire Challenge Courses of Fire | NSSF Rimfire Challenge Rulebook

Many different stage designs can be employed at Rimfire Challenge matches. Here are two examples from the NSSF Rimfire Challengs Suggested Courses of Fire:

Permalink Competition, Shooting Skills 3 Comments »
April 6th, 2014

Can Carbon Build-Up Inside Cases Alter Pressure?

As a cartridge case is reloaded multiple times, burnt powder residue and carbon builds up on the inside of the case. Unless the case interior is cleaned in some fashion, eventually you’ll see a reduction in case capacity. One of our Forum members from Australia wonders about the effects of reduced case capacity: “If the capacity of the case decreases as the crud builds up, then it effectively reduces the chamber size. Wouldn’t that change the pressure produced from that of an equivalent clean case?”

Ultrasonic Cleaning Example:

Interesting Test of Case Capacity Changes
Forum member Fred Bohl has actual test results that can help answer the above question. Fred proved that, over a 20-reload cycle, the case capacity of uncleaned cases did, indeed, decline a small amount. However, surprisingly, this did not seem to affect the actual chronographed velocity of the load. ES did increase, but Fred believes the higher ES was due to changes in case-neck tension, rather than due to the slight reduction in case capacity.

Fred reports: “Back when beginning to use ultrasonic case cleaning, part of the motivation was to get the inside clean based on the assumption that allowing burnt residue to build up inside cases would affect capacity, and, ultimately, performance. An experiment was done to test this hypothesis. The load used, 30.5 grains of RL15 behind 107gr SMKs in a 6mmBR, was selected for best group and lowest ES in prior load development. It turned out to be 92% of initial case capacity and neither “full” or compressed. (I would suspect that different powders, load weight, and total case capacity might produce very different results.)

We took 30 cases of identical initial capacity and tracked three lots of 10 each:

LOT 1: No Internal cleaning
LOT 2: Cleaned with media in tumbler
LOT 3: Cleaned with Ultrasound machine

Each case (in each lot) was shot and reloaded 20 times. The simplified results after 20 reloads of each lot were as follows:

Lot 1 (not cleaned) – 0.3 to 0.4 gr. loss of capacity, 5 to 8 fps greater ES.
Lot 2 (tumble cleaned) – 0.1 to 0.3 gr. loss of capacity, 4 to 6 fps greater ES.
Lot 1 (ultrasonic cleaned) – no loss of capacity, no detectable change in ES.

FINDINGS
There was no detectable correlation of velocity change to the lots. An oddity was that on very hot days Lot 1 velocities were, occasionally, slightly higher. [Editor’s note: That does suggest that the carbon build-up inside the uncleaned cases might cause a slight increase in pressure that shows up on hot days. Fred has posted that “A local shooter reported doing the 20 reload, no clean test on a .308 that gave a loss of capacity of 2.0 grains, doubled ES and signficant velocity changes. However, I don’t have any details on his load weight or powder.”]

NOTE: From results of another ongoing test, I believe the above differences in ES are probably due more to variance in bullet grip tension than case capacity. The ultrasound cleaned cases (LOT 3) did maintain the lowest ES, but we are not 100% sure of the reasons why. More consistent bullet seating might be the reason.

[Editor’s comment: Jason found that with his ultrasonically-cleaned cases, the inside of the necks got so “squeaky clean” that he needed to use dry lube in the necks. Jason uses the $10.95 dry lube kit from Neconos.com. This applies ultra-fine Moly powder to the neck using small carbon steel balls]

Neconos.com moly neck lube

Permalink Reloading, Tech Tip 3 Comments »
April 6th, 2014

Tech Tip: How to Cast your Chamber using Cerrosafe

by Bill Gravatt
(This article was written when Bill was President of Sinclair International, Inc.
)
Chamber casting is an easy task for the handloader to perform. A chamber casting is valuable if you run across a firearm that you believe has a custom barrel on it and you want to find out the dimensions of the chamber. Some gunsmiths will chamber a barrel and not mark it properly with the neck dimension or the exact cartridge name or specifications. We also get calls from some customers that have military firearms without cartridge stampings on the barrel; this will help these shooters identify their chambering.

cerrosafe

Another reason to make a chamber casting would be for a die manufacturer to manufacture custom dies for you. A chamber casting is often required when fired cases are not available. Some reloaders will make a chamber casting that shows them the exact configuration of the throat and leade so they can determine what bullets to try. Shooters using cast bullets will make a cast so they can choose a mould that better fits their throat taper and grove/lands diameter.

A product called Cerrosafe is the most common, reliable, and the safest material to use for making chamber castings. Cerrosafe is a metal alloy that has some unique properties which make it ideal for chamber casting. First, it has a relatively low melting point of 158 to 190° Fahrenheit. This makes it easy for the handloader to melt the Cerrosafe in his home shop. Second, it shrinks slightly during cooling which allows it to be extracted from the chamber easily. It then re-expands to the chamber’s original size after about one hour at room temperature. After cooling for about 200 hours, the chamber cast will expand to about .0025″ larger than the actual chamber size. Most good reloading die makers are used to working from Cerrosafe chamber casts.

As we said, using Cerrosafe is fairly easy and comes with complete instructions.

Making a Cerrosafe Chamber Cast — Step by Step:

1. First, clean and dry the chamber and barrel thoroughly.

2. Disassemble the firearm as necessary to gain access to the chamber.

3. Insert a tight fitting cleaning patch with a jag into the bore from the muzzle end to form a plug for the Cerrosafe. The patch should be positioned in the bore, just forward of the throat by approximately ½” to 1”.

4. Heat a Cerrosafe ingot in a small ladle. A heavy cast iron bullet caster’s ladle works fine or a plumber’s ladle. Any source of heat will do (a small propane torch will work fine).

5. Pour the Cerrosafe into the chamber until a little mound forms at the rear of the chamber. Too much and it can become more difficult to remove the cast from the chamber. If this happens, simply heat the barrel a little and re-melt the Cerrosafe. Don’t worry, your barrel gets a bit hotter than 190 degrees during firing.

6. The chamber can be difficult to access, so some people find it easier if they make a pouring tube out of steel, brass, or aluminum tubing to funnel the Cerrosafe into the chamber.

7. After the Cerrosafe has hardened, the chamber casting can be pushed out of the chamber coming from the muzzle end using a cleaning rod or a wooden dowel. It is recommended that you push it out within a half-hour of casting the chamber. We usually push our cast out within a few minutes. If the cast does not push out easily, insert a cleaning rod from the muzzle and tap the rod handle with the palm of your hand to start the cast out of the chamber. You can put a paper towel in the action to catch the cast or lay the rifle on the bench with a towel or bench mat underneath it to catch the cast as it falls from the action. This will prevent damage to the cast.

8. Take your measurements shortly after one hour of cast, and then put the casting away until you need it again. A medicine container or something similar makes a great container. If you are going to keep the cast be sure to mark the cast or the storage container so you know which rifle it came from. If you have no need to keep the cast you can re-melt the Cerrosafe and use it again when you need to make another cast.

This article originally appeared in Sinclair International’s The Reloading Press Blog.
Permalink Gunsmithing, Tech Tip 5 Comments »
April 6th, 2014

Coupons for Free Flashlight, Multimeter, Screwdriver Set and More

Free is good. Especially when “free” is the real deal, meaning no purchase required, no strings attached. And that’s what we’ve got here. Now through April 30, 2014, Harbor Freight is offering six products, absolutely free (with coupon). You can get a tape measure, flashlight, multimeter, tarp, screwdriver set, or scissors. Just print the coupon and take it to the store. You don’t have to buy anything else — but there is a limit of ONE ITEM per day per customer. So you can’t go to the store and get all six items on the same day. (But you could return multiple times and get a different item). NOTE: Before you print out these coupons, click the images below to display the 100% scale version. The coupons below have been downsized to fit our Daily Bulletin — this may make the bar codes harder to scan.

Click coupon images to get larger version for printing
free products at Harbor freight

free products at Harbor freight

Product tip from EdLongrange. We welcome reader submissions.
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