Frequently Asked Questions
Documentations:
- What is an EREK knob
- What knobs are available for what scopes?
- Should I choose MOA or MIL values?
- How do I have a custom made BDC? What info is needed?
- Why does a 10X scope have more elevation travel than a 22X?
- Is the complete reticle lit?
- Why is my reticle upside down and backwards?
- Do I need to lap USO rings?
- What does a larger objective do for me?
- What does TPAL mean?
- What type of battery does the lit reticle use?
- What color anodizing is available?
- What height ring do I need?
- What is the small “dent” in my MST-100/150?
- Why a larger tube diameter?
- My reticle appears to have dust on it, what is this?
EREK knob
Erector Repositioning Elevation Knob.
This is a 90 clk/rev system. It comes in 1/4MOA, 1/2MOA, and 1cm@100m per click subtentions. This knob has about 80MOA elevation travel and can be repositioned on the erector screw to simulate a down angle base. This is important to flat-tops and other 0MOA down base rifles because they only get half of a scopes effective travel as well and very long range shooters.
The EREK is an elevation knob only and is available on the SN-3 and ST-10 models.
What knobs are available for what scopes?
This is a bit of a difficult question because of all the scopes we produce, but we will try to give you a brief list.
- EREK- Available on all SN-3 models and ST models
- U.S.#1- All scopes
- U.S.#1 M40- All scopes
- U.S.#2- SN-9 only
- U.S.#3- All SN-3 and ST models
- Slimline knobs- SN-4, SN-12, SN-3 and ST-10 in 10X only (17X coming soon)
- Zeroing knobs- SN-4 and SN-12
Should I choose MOA or MIL values?
This is like picking what Playboy Playmate you like more, this is total personal preference.
MOA is close to inches, which make sense to many people that live in the U.S. because of our measurement system. MIL values are nice because the math is very easy, base 10 like the metric system.
All knobs are offered in MOA or MIL values, match them up with your favorite MOA or MIL reticle for a deadly combination.
How do I have a custom made BDC? What info is needed?
We can crunch numbers hear for you based on your ballistic information then engrave a new knob for you. To make certain that the knob is dead on, it is preferred that the customer send us his or her proven ballistic information. What we like to have is either the number of clicks between yardages, or MOA/MIL numbers.
If you want us to crunch the numbers in our ballistic calculator, you must provide us with the following,
- Bullet weight
- Bullet ballistic coefficient
- Velocity
- Average altitude
- Average temperature
Please contact one of our customer service representatives for immediate help.
Why does a 10X scope have more elevation travel than a 22X?
To put it simply, the EFL (effective focal length) of the objective. The longer the focal length of the objective the less elevation travel the scope will have.
Also, this creates different click values for the elevation and windage knobs. A ¼ MOA knob on a 10X scope will not work on a 22X scope. Since our scopes are FFP the reticle in a 10X scope will NOT work in a 22X.
Is the complete reticle lit?
In most cases the complete reticle is lit. The MDMOA and the Horus reticles are available with only portions lit.
Why is my reticle upside down and backwards?
The very 1st time we heard this question asked we had no answer. We finally figured out the customer was looking trough the wrong end of the scope.
This is most common with the SN-4 and SN-12 models because the objective is smaller than the eyepiece.
Do I need to lap USO rings?
No, you do NOT have to lap our rings. Our rings along with our bodies are coated with Type III anodizing, which is extremely hard. If you were to use a standard lapping bar you would end up destroying it. Also, because the rings are windage adjustable, both side feet move and allow you to clamp to the scope first, then adjust for windage.
What does a larger objective do for me?
A larger objective will provide better light gathering capabilities. In most conditions you will not notice any difference between the 44 and 58mm. Where you will notice the difference is first thing in the morning or at dusk, the first and last few minutes before it is dark. In some cases the 58mm will require that you use an optional sunshade to cut down on the light.
What does TPAL mean?
TPAL stands for turret parallax, this is the knob usually found on the left side of the turret on most scopes.
What type of battery does the lit reticle use?
The rheostat uses a CR2032 coin type battery that is fairly common.
What color anodizing is available?
We can do just about any color anodizing that you would like in Type II anodizing. Type II anodizing is what most other scope manufactures use, it is not as strong as the Type III anodizing we use on our black and OD green scopes. Type III is available in black, OD green, dark grey, dark blue, and dark brown. If you are looking to build a custom competition rifle and crazy colors are OK, we can do just about any color in Type II
What height ring do I need?
This is a difficult one. Most ring heights can be figured out based on your height base and objective diameter. If you are using a 44mm objective, most likely you will need either a "X-low" or "Low" on a bolt gun with a standard base. If you are using an AR flat top design you are going to need a "medium" or "high". Most cases the 'high" provides a cheek postion that is a bit more comfortable, "medium" is a bit too low. 58mm objective will need a "low" or "medium' on most bolt guns.
What is the small "dent" in my MST-100/150?
This is a carefully placed dent that keeps the objective from rotating in the housing when adjusted.
Why a larger tube diameter?
The larger the tube diameter the more room you have to move the internal erector tube. In return you are able to obtain more total MOA travel out of the scope. This is important in some cases where the power of the scope is 22 or 25X and more elevation travel is needed.
My reticle appears to have dust on it, what is this?
The bodies of our scopes are machined with light break ups and then coated with Type III hard anodizing to reduce the unwanted stray light. Sometimes a small particle become loose and is attracted to the static properties of the glass reticle in the front focal plane. Since the reticle is under extreme magnification the dust particle appear to be very large. Most cases the particle will fall off of the reticle and stick to the grease that is on the inside of the tube. Sometimes it is necessary to help the duct along a bit. This can be done by shooting the rifle, taking a drive down a dirt road with the rifle, tapping the scope with a rubber mallet or anything that will give it a jar.