November 17th, 2020

CZ 457 Long Range Precision (LRP) Rimfire Rifle

CZ 456 long range precision LRP tactical PRS NRL22 rimfire .22 LR 22LR rifle

Earlier this year, CZ introduced a new .22 LR rifle for shooters looking for a PRS/NRL rimfire cross-trainer or a bolt gun for NRL22 competition. This new CZ 457 Long Range Precision (LRP) model features a 20″ fluted barrel with factory-installed muzzle brake. The stock adjusts for length-of-pull and has an adjustable cheekpiece. On top of the action is a +25 MOA Weaver-type rail so you have enough elevation to shoot out to 300 yards and beyond with most scopes. The single-stage trigger is also adjustable. MSRP is over $1200.00 but this rifle is now available for $899.99 at KYGunCo.com.

CZ factory video shows features of CZ 457 LRP:

CZ 456 long range precision LRP tactical PRS NRL22 rimfire .22 LR 22LR rifle

The LRP’s target stock boast textured grip surfaces and a near-vertical pistol grip. The rear has a “hook” for positions where the shooter will use his non-shooting “off” hand to steady the rear of the rifle when the front is on a bag or support. The rear rail allows quick installation of monopod or bag-rider. There is a very fat, oversized bolt knob. A five-round magazine is standard with 10-rounders availalble.

The height of both the comb (cheekpiece) and buttpad are adjustable. Also the length-of-pull can be adjusted with the four included spacers (351-382 mm).

CZ 457 LRP Specifications:
Caliber: .22 LR
Barrel: 20.66″, hammer-forged, fluted
Barrel Twist Rate: 1:16″
OAL Length: 39.76″
OAL Weight: 8.3 pounds
Rail: +25 MOA Elevation
Trigger: Adjustable
Cheekpiece: Adjustable for Height
Buttpad: Adjustable for Height
LOP: Adjustable with Spacers
Stock: Beech with Soft-touch Finish
Muzzle Brake: Standard

Click Image to see full-screen photo of CZ 457 LRP
CZ 456 long range precision LRP tactical PRS NRL22 rimfire .22 LR 22LR rifle

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November 17th, 2020

TECH TIP: Bullet Bearing Surface Length Can Affect Pressure

USAMU Bullet Ogive Comparision Safety Reloading
Photo 1: Three Near-Equal-Weight 7mm Bullets with Different Shapes

TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).

Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284″) very near the cannelure. This taper is often seen on similar bullets — it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430”, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!


This article from the USAMU covers an important safety issue — why you should never assume that a “book” load for a particular bullet will be safe with an equal-weight bullet of different shape/design. The shape and bearing surface of the bullet will affect the pressure generated inside the barrel. This is part of the USAMU’s Handloading Hump Day series, published on the USAMU Facebook page.

Beginning Handloading, Part 13:
Extrapolating Beyond Your Data, or … “I Don’t Know, What I Don’t Know!”

We continue our Handloading Safety theme, focusing on not inadvertently exceeding the boundaries of known, safe data. Bullet manufacturers’ loading manuals often display three, four, or more similar-weight bullets grouped together with one set of load recipes. The manufacturer has tested these bullets and developed safe data for that group. However, seeing data in this format can tempt loaders — especially new ones — to think that ALL bullets of a given weight and caliber can interchangeably use the same load data. Actually, not so much.

The researchers ensure their data is safe with the bullet yielding the highest pressure. Thus, all others in that group should produce equal or less pressure, and they are safe using this data.

However, bullet designs include many variables such as different bearing surface lengths, hardness, and even slight variations in diameter. These can occasionally range up to 0.001″ by design. Thus, choosing untested bullets of the same weight and caliber, and using them with data not developed for them can yield excess pressures.

This is only one of the countless reasons not to begin at or very near the highest pressure loads during load development. Always begin at the starting load and look for pressure signs as one increases powder charges.

Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In photo 1 (at top), note the differences in the bullets’ appearance. All three are 7mm, and their maximum weight difference is just five grains. Yet, the traditional round nose, flat base design on the left appears to have much more BSL than the sleeker match bullets. All things being equal, based on appearance, the RN/FB bullet seems likely to reach maximum pressure with significantly less powder than the other two designs.

Bearing Surface Measurement Considerations
Some might be tempted to use a bullet ogive comparator (or two) to measure bullets’ true BSL for comparison’s sake. Unfortunately, comparators don’t typically measure maximum bullet diameter and this approach can be deceiving.

Photo 2: The Perils of Measuring Bearing Surface Length with Comparators
USAMU Bullet Ogive Comparision Safety Reloading

In Photo 2, two 7mm comparators have been installed on a dial caliper in an attempt to measure BSL. Using this approach, the BSLs differed sharply from the original [measurements]. The comparator-measured Bullet 1 BSL was 0.694” vs. 0.324” (original), Bullet 2 was 0.601” (comparator) vs. 0.430” (original), and Bullet 3 (shown in Photo 2) was 0.602” (comparator) vs. 0.463” (original). [Editor’s comment — Note the very large difference for Bullet 1, masking the fact that the true full diameter on this bullet starts very far back.]

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November 17th, 2020

Precision Load Development Target — And Printing Tips

FREE Accuracy Precision Rifle Shooting Target
Right-Click target image to download printable PDF.

We created the above target a decade ago. Since then it has been used by tens of thousands of shooters. It has proven very popular as a load development target, since all your load data fits neatly in the boxes under each target. In fact this target is being employed by both rifle-makers and barrel-makers (including Criterion) to test their products. The target was designed for aiming efficiency. The diamonds have 1/2″ sides and you can align your reticle cross-hairs on the horizontal and vertical lines. It is a clean design that is easy to see even at 200 yards with a 20X scope. When we test, we usually crank in a little elevation, setting the point-of-impact higher, so that our shots fall in the gray circles. That way you leave the red diamonds intact for precise aiming. CLICK HERE to download Load Dev target.

We also use these two targets for load development and precision practice.
The circle dot target can also be used for informal rimfire competition at 50 yards.
Right-Click Each Target to Download Printable PDFs.

FREE Accuracy Precision Rifle Shooting Target FREE Accuracy Precision Rifle Shooting Target


GET 50 More FREE Targets on AccurateShooter Target Page »

Printing Targets card stock heavy paper benchrestHow to Print Your Targets
Most of us have access to a printer at home or at work. That means you can print your own targets. You’ll find hundreds of free target designs online, including dozens of downloadable targets on our AccurateShooter.com Target Page. If you’re feeling creative, you can design your own target with a computer drawing program such as MS Paint.

Paper Stock Is Important
If you want your self-printed targets to show shots cleanly (and not rip when it gets windy), you should use quality paper stock. We recommend card stock — the kind of thick paper used for business cards. Card stock is available in both 65-lb and 110-lb weights in a variety of colors. We generally print black on white. But you might experiment with bright orange or yellow sheets. Forum Member ShootDots report: “They sell cardstock at Fed-Ex Kinko! I use either Orange or Yellow. That makes it easy to see the bullet holes clearly.” NOTE: Test before you use the 110-lb Cardstock. On some printers, with the heavier 110-lb card stock, you will need to have the paper exit through the rear for a straighter run.

Printing Targets card stock heavy paper benchrest

Here are some Target-Printing Tips from our Forum members:

“Staples sells a 67-lb heavy stock that I have settled on. I use the light grey or light blue, either of these are easy on the eyes on bright days. I have used the 110-lb card stock as well and it works fine. It’s just a little easier to print the lighter stuff.” (JBarnwell)

“Cardstock, as mentioned, works great for showing bullet holes as it doesn’t tear or rip like the thin, lightweight 20-lb paper. I’ve never had a problem with cardstock feeding in the printer, just don’t stick too many sheets in there. If I need three targets, I load only three card stock sheets”. (MEMilanuk)

“20-lb bond works pretty well for me if I use a spray adhesive and stick the entire back of the paper’s surface to the backer board.” (Lapua40X)

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