The Ballistic Tools case mouth and neck tension gage tells you exactly how much neck tension your reloads will have.

Measuring neck diameter with calipers is an iffy proposition at best. A small burr on the case mouth, a slight angle to the calipers, or even just placing too much tension on the calipers can give distorted readings. Improper neck tension can make projectile insertion more difficult, or even cause a safety issue if the neck is too loose.

Using our gage solves all those problems. It can knock off a small burr during insertion, and will not distort the round shape of the mouth like calipers will.

This gage is for 224 diameter and 308/310 diameter brass. It will do calibers such as .223 Remington, 5.56 NATO, 7.62 NATO, .308, .30/06, 7.62x39, and many more.

On the 308/310 side, the gage diameters are .299, .302, .305, .308, and a smaller step at .310 for 7.62x39.

Ideal neck tension for 308 diameter would indicated when the gauge slides to the second or third stop. If the gauge will not insert, neck tension is excessive and may cause seating problems, if the .308 mouth brass slides all the way to the small .310 stop, it is too loose to retain a bullet. Use moderate pressure when gauging to ensure you are on the correct stop.

For 7.62x39, 32 caliber pistol, or lead cast .308, projectile diameter is often .310-.312, which is why there is an extra small .310 step for those.

The .224 side works the same as the 308, in that the case mouth should generally gauge to the second or third stop and not slide all the way to the handle.

This case mouth gage is a quick and reliable way to test your neck sizing and neck tension. It is a tool I developed for my own use and I could not do without it. Order yours today.

More Information

More Information
Type of product	Gauges
Barcode	857042005025
SKU	ballis-cmg-001
Brand	Ballistic Tools

Reviews

Ratings & Reviews

Be the first to review this product

FAQ

FAQ - Frequently Asked Questions

Welcome to our purchasing FAQ! Here you'll find answers to our most asked questions regarding purchasing from us. If you are after Reloading FAQ's, please click HERE, where you can find more specific question and answers. Still can't find quite what you're looking for, or have something we should know? Send us an email, we're happy to help!

Q1: Do you ship to my country?

A1: European countries (All items except Ammunition, Powders, Primer, Cases & Projectiles)
Q2: How much do I pay for shipping?

A2: The shipping charge will be added to your order and visible on your receipt before you check out. The shipping is based on the destination country. You’ll get free shipping on orders above a certain amount.

Free shipping on orders above: £50 for mainland UK next day deliveries.

France - £25
Norway – £45
Finland – £46
Germany – £25
UK – £5 (Free UK Mainland with purchases over £50)
Rest of the EU – £25-100
Global – £100-200
Q3: What are the accepted payment methods?

A3: We accept online card payment with MasterCard, VISA, Worldpay or Bank Direct Debit
Q4: What currency do I pay in?

A4: The currencies used are GBP, EUR & USD The currency is chosen automatically depending on your shipping country.
Q5: When do I receive my order?

A5: We dispatch all orders in 1-2 business days with DPD & Parcelforce, delivery time will depend on the shipping country and address.
Q6: Do I have to pay international taxes and duties?

A6: Your order may be subject to import duties and taxes, which are levied once a shipment reaches your country. We cannot control and is not responsible for any duties/taxes applied to your package upon delivery. You will be responsible for paying additional charges for customs clearance. Customs policies vary widely from country to country; please contact your local customs office for further information.

Ten Commandments

Set up your reloading bench where it (and stored components) will not be exposed to heat, sparks or flame.
Establish a comfortable loading procedure and don't vary it.
Keep your reloading bench, equipment and area clean and uncluttered. Label components and reloads for safe, easy identification. Never use powder from an unlabelled tin.
Understand what you are doing and why it must be done in a specific way.
Follow loading recommendations exactly. Don't substitute components for those listed in metallic data without reducing the load and working back up.
Never substitute smokeless powder for black powder or Pyrodex because smokeless powder is much more powerful than black powder. Never mix two powders together.
Wear safety glasses.
Stay alert when reloading. Don't reload when distracted, disoriented or tired.
Don't smoke, drink alcohol or take drugs while reloading or while in your reloading area.
Keep everything out of reach of small children.

Calibre Identification

Rifle Calibre Name	Common Metric Name	Bullet Diameter
.17	4.5mm	.172"
.204	5.2mm	.204"
.223	5.56mm	.224"
.22 (Rimfire)	5.6mm	.223"
.22 (Centrefire)	5.6mm	.224"
.243	6mm	.243"
.257	6.53mm	.257"
.260	6.5mm	.264"
.270	6.8mm	.277"
.280	7mm	.284"
.30	7.62mm	.308"
.325	8mm	.323"
.33	8.6mm	.338"
.366	9.3mm	.366
.375	9.5mm	.375"
.416	10.6mm	.416"
.50	13mm	.510"