September 22nd, 2017

The Science of Annealing — Facts Uncovered, Myths Busted

Annealing Made Perfect Testing AMP cartridge Case hardness Lapua Norma Lake City

The science behind annealing during the manufacture of new cases is well-established. What happens after that, when we repeatedly reload and anneal those same cases, has always been somewhat of a “dark art”. To help separate scientific fact from fiction, the creators of the Annealing Made Perfect (AMP) Annealer machine have conducted detailed studies of cartridge brass. The AMP Team’s studies offer some remarkable insights, while disproving a number of myths about annealing. Will annealing tighten your groups? The evidence of these studies shows it could.

The test results are fascinating. The team compared brands of brass, sectioning brass to examine both alloy composition and thickness from case mouth to case-head (bottom). They also examined how carbon build-up affects next tension. And they determined how brass changes over multiple loading cycles. They even did a series of bullet-pull tests to analyze factors affecting neck tension. Here are some of the key subjects in the reports:

Brand by Brand Analysis — How the cartridge brass alloy varies among different manufacturers.
Bullet Release and Neck Tension — Tensile Bullet-Pull tests show factors affecting neck tension.
Neck Tension and Carbon — How carbon build-up inside the neck affects “neck tension”.
SS Tumbling and Hardness – How tumbling with stainless media affects brass hardness.
Case Cleaning (Ultrasound and Tumbling) — How case cleaning affects annealing.
Multiple Loadings — How brass performs when annealed every reload over 10+ cycles.

Annealing Made Perfect Testing AMP cartridge Case hardness Lapua Norma Lake City

You really should read the reports — there are some fascinating revelations. The AMP team made longitudinal sections of various cases to show different case wall thicknesses and head geometry. These examples also show how the hardness of the case varies from the case mouth to the case-head. Both virgin and used, annealed cases were examined.

Bullet-Pull Tests — Using advanced tensile test equipment, AMP experimented with different combinations of dies, reloading sequences, and neck hardness to ascertain the best practice.
Annealing Made Perfect Testing AMP cartridge Case hardness Lapua Norma Lake City

Carbon Inside Your Case-Necks May Be a GOOD Thing
AMP’s testers found carbon in necks can be beneficial: “Even with identical interference fit and neck hardness, as the carbon layer increased (microscopically), the force to draw the bullet decreased. It would appear the carbon acted as a lubricant. Interestingly, the [pull force] standard deviation also improved, i.e. the case to case variation in the force required to draw the bullets decreased.”*

Read the Full Test Reports

The AMP team’s objectives were to clarify some misconceptions on just what annealing does and does not do, and also to establish the best practices for consistent results. They have consulted with three independent certified metallurgy laboratories to produce some definitive information. So far, the Stage 1 and Stage 2 reports have been released. The studies include a report on the general physical properties of cartridge brass, including grain structures, hardness scales, time/temperature annealing information, and what can cause de-zincification.

The FULL REPORTS, including comprehensive appendices, are found here:

Stage One: https://www.ampannealing.com/articles/40/annealing-under-the-microscope/

Stage Two: https://www.ampannealing.com/articles/42/annealing-under-the-microscope/

Annealing Made Perfect Testing AMP cartridge Case hardness Lapua Norma Lake City

Examining Different Brands of Brass — What the Tests Revealed

Is Lapua brass harder than Norma? Is Lake City better than Remington? You’ll find answers to these and other questions in AMP’s annealing studies. One of the key findings in Stage 2 of Amp’s research is that brass from different manufacturers does vary in the distribution of material in the walls of the case.

Annealing Made Perfect Testing AMP cartridge Case hardness Lapua Norma Lake City

Stage Two Conclusions:

— Different brands of the same cartridge cases can require different annealing power settings due to differing case wall thickness in the neck and shoulder region. The greater the mass of brass to be annealed, the greater the power requirement. Lot to lot variation within the same brand can occur for the same reason.

— The bushing die used in this set of tensile bullet pull tests gave significantly more consistent results than the standard neck die with expander ball.

— Cases should be annealed every reload in order to get the best repeatability.

Case Variations: Brand to Brand, and Lot to Lot

Here is a sample from AMP’s test report:

Analyzing Different Brands of Brass
In our Stage One report, we demonstrated that there is insufficient variation in alloy composition between brands to account for the variations we experience when annealing different brands of the same cartridge case. We therefore sought to confirm that it is the mass of brass to be annealed which accounts for the difference. Below are sectioned samples of four different brands of .223 Remington cases.

Both the Lapua and Norma neck walls are 314* microns (0.01236”) at the mouth. The Lapua neck wall thickens to 348 microns at the junction of the neck and shoulder, and the Norma neck thickens to 325 microns. Through the shoulder, however, the walls of both cases thicken to 370 – 380 microns. Once past the shoulder, they both taper back to 314 microns, before starting to thicken again, moving towards the case head.

The Lapua case requires AMP Program 47 to anneal correctly. It is the heaviest of the four cases tested through the shoulder region. The Norma case, which is only slightly lighter through the same region, needs Program 43.

The Remington case is very similar to the Lapua and Norma cases in the neck region, but it actually thins fractionally through the shoulder and front section of the body. The AMP program setting for Remington 223R is P32.

The Lake City case is the thinnest throughout of all four samples. It only requires Program 28.

The above samples clearly demonstrate that the mass of brass to be annealed is critical to the power requirement for correct annealing.

To see how the AMP Induction Annealing Machine works, watch this video:

* However, in Stage Two of AMP testing, the testers experimented with clean, carbon-free necks with dry lube. There was some indication of greater tensile pull consistency with dry-lube, but AMP plans to do more testing.

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September 22nd, 2017

Seeing Bullet Holes at 1000 Yards — the Ultimate Optics Challenge

Pentax PF 100ED

Pentax smc-xw 10mmWhile attending the CA Long Range Championship a few seasons back, we had the opportunity to test the performance of a high-magnification (63X) spotting scope in near-ideal conditions (maybe the best I’ve ever witnessed). On the event’s last day we arrived at 5:45 am, literally as the sun was cresting the horizon. I quickly deployed our Pentax PF-100ED spotting scope, fitted with a Pentax SMC-XW 10mm fixed-power eyepiece. When used with the 100mm Pentax scope, this 10mm eyepiece yields 63X magnification. Befitting its $359.00 price, this eyepiece is extremely clear and sharp.

At the crack of dawn, viewing conditions were ideal. No mist, no mirage, no wind. The first thing this Editor noticed was that I could see metal nail heads on the target boards. That was astonishing. As soon as the first practice targets went up, to my surprise, I could see 6.5mm, 7mm, and 30-caliber bullet holes in the white at 1000 yards. No lie…

That’s right, I could see bullet holes at 1000. I know many of you folks may not believe that, but there was no mistaking when I saw a 7mm bullet cut the white line separating the Nine Ring and Eight Ring on the target in view. (I was watching that target as the shot was fired and saw the shot-hole form). And when I looked at the 30-cal targets, the bullet holes in the white were quite visible. In these perfect conditions I could also make out 3/8″ bolt heads on the target frames.

The Human Factor
When viewing the bullet holes, I was using my left naked eye (no safety glasses or magnification). I also had a contact lens in my right eye (needed for distance vision). To my surprise, while I could see the bullet holes without much difficulty with my left eye, things were fuzzier and slightly more blurry with the right eye, even when I re-focused the scope.

Pentax smc-xw 10mmThen I invited 3 or 4 shooters to look through the scope. One younger guy, with good eyes, said immediately: “Yeah, I can see the holes — right there at 4 o’clock and seven o’clock. Wow.” Some older guys, who were wearing glasses, could not see the holes at all, no matter what we did to the scope’s main focus and diopter adjustment.

The lesson here — if you have to wear glasses or corrective contact lenses, just that extra bit of optical interference may make a difference in what you can see through the scope. Basically anything that goes between the scope eyepiece and your eyeball can degrade the image somewhat. So… you may be better off removing your glasses if you can still obtain good focus sharpness using the diopter adjustment and focus ring. I did the left vs. right eye test a half dozen times, and I could definitely see small features at 1000 yards with my naked eye that I could not see with my right eye fitted with a contact lens. (I did have to re-focus the scope for each eye, since one had a corrective lens while the other did not.)

Mirage Degrades Image Sharpness and Resolution
The “magic light” prevailed for only an hour or so, and then we started to get some mirage. As soon as the mirage appeared I was no longer able to see raw bullet holes, though I could still easily see black pasters on the black bulls. When the mirage started, the sharpness of the visible image degraded a huge amount. Where I could see bullet holes at dawn, by mid-morning I could barely read the numbers on the scoring rings. Lesson: If you want to test the ulimate resolution of your optics, you need perfect conditions.

Chromatic AberrationChromatic Aberration Revealed
As the light got brighter and the mirage increased I started to see blue and red fringing at the edges of the spotting disk and the large numerals. This was quite noticeable. On one side of the bright, white spotting disc you could see a dark red edge, while on the other side there was a blue edge (harder to see but still present).

The photo below was taken through the Pentax spotter lens using a point and shoot camera held up to the eyepiece. The sharpness of the Pentax was actually much better than this photo shows, but the through-the-lens image does clearly reveal the red and blue fringing. This fringing is caused by chromatic aberration — the failure of a lens to focus all colors to the same point. Chromatic aberration, most visible at high magnification, causes different wavelengths of light to have differing focal lengths (see diagram). Chromatic aberration manifests itself as “fringes” of color along boundaries that separate dark and bright parts of the image, because each color in the optical spectrum cannot be focused at a single common point on the optical axis. Keep in mind that the Pentax does have “ED” or low-dispersion glass, so the effect would be even more dramatic with a cheaper spotting scope.


CLICK HERE to view LARGE PHOTO that shows aberration more clearly.

If you wonder why top-of-the-line spotting scopes (such as the $3900 Leica APO-Televid 82) cost so much, the answer is that they will deliver even LESS chromatic aberration at long range and high magnification. With their exotic apochromatic (APO), ultra-low-dispersion glass, a few ultra-high-end spotting scopes can deliver an image without the color edging you see in the photo above.

The Pentax PF-100ED is a heck of a spotting scope. Any scope that can resolve bullet holes at 1000 yards is impressive. But if you want the ultimate in optical performance, with minimal chromatic aberration, you may need to step up to something like the 88mm Kowa Prominar TSN-883 with Flourite Crystal lenses ($2450.00 body only), or the 82mm Leica APO ($3899.00 with 25-50X eyepiece).

EDITOR’s NOTE: The purpose of this report is to show what is possible… in IDEAL conditions. With this Pentax 100mm, as well as a Swarovski 80mm, we have often been able to resolve 6mm bullet holes at 600 yards. But again, that performance requires really good viewing conditions. By 10:00 am at my range, even with the 100mm Pentax at 75 power, seeing 6mm bullet holes is “iffy” at best. So don’t go out and mortgage the house to buy a $4000 optic with the hope that you’ll be able to spot your shots at 1000 yards. If conditions are anything less than perfect, you’ll be lucky to see bullet holes at 500 yards. The real solution for very long-range spotting is to set up a remote target cam that broadcasts a video picture to a screen at your shooting station.

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September 22nd, 2017

Great Deal on 6.5 Creedmoor Howa for PRS and Tac Comps

Howa HCR Chassis Rifle PRS Tactical Aluminum stock HACT Trigger

Here’s a great deal if you are looking for a smooth-running 6.5 Creedmoor rig in a modular chassis for PRS and tactical competitions. Right now you can get the Howa HCR chambered in 6.5 Creedmoor for just $867.00 at Bud’s Gun Shop (Check, eCheck or M/0 price). The new Howa HCR (Howa Chassis Rifle) combines a Howa 1500 barreled action with a modern, fully-adjustable aluminum chassis. MSRP for this HCR rifle is $1299.00, so this $867.00 price is a great deal for a 6.5 Creedmoor Howa with a very good two-stage trigger and 1:8″-twist 24″ barrel. Other chamberings are: .223 Remington, .243 Winchester and .308 Winchester (price may vary).

Mounted on an AR-style buffer tube system, the Howa HCR utilizes the fully adjustable LUTH-AR MBA-3 stock. Length of Pull is adjustable from 12.5″ to 16.75″. Comb height is also adjustable to fine tune for scope height-over-bore. Weight with a 24″ barrel is 10.2 pounds (before optics), so this Howa HCR is lighter than some similar rifles on the market.

Howa HCR Features

• Howa 1500 Barreled Action with 24″ Heavy Barrel
• Black 6061-T6 Aluminum Chassis with Free-Float M-LOK Forend
• LUTH AR Buttstock with LOP Adjustment (12.5″ to 16.75″) and Adjustable Comb
• 10-RD ACCURATE Detachable, Teflon-coated Steel Magazine
• Two-Stage H.A.C.T. Trigger
• 3 Position Safety

Howa HCR Chassis Rifle PRS Tactical Aluminum stock HACT TriggerThe HOWA HCR features an adjustable, two-stage HACT trigger, set for about 3 pounds (combined stages). Crisp and repeatable, this is an excellent trigger for a factory gun. In our opinion, the HACT trigger is clearly superior to the trigger on the Ruger RPR, as well as the Savage AccuTrigger. And there is no annoying Glock-style safety lever in the middle of the trigger blade.

Also available in .223 Rem, .243 Win, and .308 Win chamberings (price may vary)

NOTE: For all chamberings, 24″ barrels are offered, with 20″ options for the .223 Rem and .308 Win as well. Twist rates are 1:9″ for .223 Rem, 1:10″ for .243 Win, 1:8″ for 6.5 Creedmoor, and 1:10″ for .308 Win. We think .243 Win shooters will NOT be happy with the 1:10″ twist. We would prefer to see a 1:8″-twist for the .243 Win so it can shoot the 105-115 grain 6mm bullets. Most competitive 6mm shooters will want a true 8-twist or even a 1:7.5″.

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