Estimating scope elevation adjustment?


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Jasper1573
January 16, 2011, 02:59 PM
This question may have been asked before, but if it has, I am not sure how to search for the answer, so...

I am planning to shoot in an F/TR competition next month at 500 yards, but my range here is only 300 yards, and I have no place to practice at 500 yards before the competition.

I have my rifle zeroed at 300 yards and based on the ballistics that my reloaded round is producing, I should need 30 or 31 additional clicks of elevation to be on at 500 yards.

Here's the DOPE....308 Winchester firing SMK 175 HPBT at 2550 fps; requires 22 up clicks on my scope at 300 yards. The on-line ballistics calculator says I should use 21 up clicks, so either the calculator is off by one click or my scope is off by one click. The ballistics calculator calls for 30 additional up clicks of elevation so since there is a difference of 1 click at 300, I suspect it will be the same at 500 yards and I plan to use 31 additional up clicks of elevation.

Question...is there a better way to figure this elevation adjustment?

Jasper

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WNTFW
January 16, 2011, 03:46 PM
What are clicks? Most shooters express in MOA. What are your click values? I assume 1/4" per 100.

To be more accurate you would need height over bore. It can make bigger difference than most realize. Seems like you have pretty close. I wouldn't be sweating over 1 click no matter what the value. Either way you should be on paper. Do you get sighters? At the matches I have been to we get 2 sighters.

At least you know your velocity. How well does the ballistic calc match from 100 to 300yds.

Jasper1573
January 16, 2011, 03:55 PM
Sorry for assuming...yes, the scope is a 1/4 MOA per click at 100 yards. After zeroing at 100 yards, it was an additional 22 up clicks, 5.5 MOA, to get zeroed at 300 yards; then another 7.75 MOA (estimated) out to 500 yards.

Yes, they allow two spotter shots on metal plates, then 20 rounds for score. I am sure my figures are close as I have calculated them manually as well as with a ballistics calculator and the numbers agree.

But is there a better way to figure this out other than actually shooting at 500 yards?

If not, I'll have to go with what I have. Again, sorry for the terminology void on my original question.

Jim Watson
January 16, 2011, 03:55 PM
One click, presumably 1/4 moa, is peanuts. The differences in actual vs table bullet BC, actual vs catalog scope adjustments, day to day weather, etc, etc, will be up in the moa range. Be glad if your first sighter is in the black, never mind within an inch.


Say, that format, two on a gong, then for record at 500 yards sounds familiar.
Does Jasper1573 signify Jasper, AL and are you going to Brock's Gap where they shoot that match?

WNTFW
January 16, 2011, 04:28 PM
Interesting how the matches vary from location to location. How big are the steel? I guess I am envisioning having a plan if sighter1 doesn't ring the steel. Not trashing you shooting - just have seen some guy have problems. Might have had some myself!!!

If you feel you have it figured and have checked your numbers, then don't use anything else. 16-16.5 is ballpark for 600yds in mine with a different load. At some point shooting is the only way to verify. DOPE is Data Obtained from Previous Engagement if I remember correctly.

Like Mr. Watson I get some variance. I put my rifle in the case with the elevation where it was for 600 & next time I may need a click or 2 up or down.

Good luck on the upcoming match. Maybe you can give us a report afterwards.

Jasper1573
January 16, 2011, 05:16 PM
Yes, Mr. Watson, the competition is at Brock's Gap. The fellow running the match is Larry Levine. He seems to be very accomodating over email, and has been very helpful with match rules, format, etc.

Hopefully WNTFW is right and I will be able to hit the metal target on my spotter shots. Mr. Levine told me that the metal plates are 10 inches with a 5 inch center.

WNTFW, when you say 16 -16.5 is ballpark for 600 yards, can you tell me are you talking 16 MOA elevation adjustment for that range? If so, are you shooting a .308 Win and what is the velocity of your round and type of projectile?

Jasper

WNTFW
January 16, 2011, 06:57 PM
Yes 16 -16.5 MOA for 600yd from a 100 yd zero

Velocity - I have no idea. It is a .308 cal 168 from wideners and a believe it is a PrivPartisan. So far I have used Varget & Reloder 15. I have a friend with a chrono but have not tried.
http://www.wideners.com/itemdetail.cfm?item_id=8439&dir=278|281|727

So far I have no reason to change to something better. I couldn't tell the difference between several preminum bullets @ 100. I figured I would just shoot these until I was not the limiting factor.

At some point in the future I will try some other bullets and test at longer than 100yds.

For our sighters we get the full 6x6 target backer. The targets are serviced after every shot. Even if pit service is a little slow it is still great to have.

Have you shot F-Class before? Or any other matches?

Jasper1573
January 16, 2011, 11:40 PM
Nope, I have never shot in competition before...I am just looking forward to shooting out past 300 yards and this is the best opportunity right now for me since we don't have a range longer than 300 yards in the Montgomery, AL area. Sounds like your shooting range set up is a little better than the one near Birmingham.

Jasper

WNTFW
January 17, 2011, 02:45 PM
Matches really are a good way to shoot and not have to join a range.

http://paloaltogunclub.com/
Any range with running water is about as good as it gets. The range is pretty nice and about 1.5 hours from my house. It was 1:15 but the parish we have to go through now gives out speeding tickets like crazy, so we had to kick down a notch.

95+% of the guys at a match are great. They will probably help you as much as they can. The emphasis is safety. You may need an ECI "Empty Chamber Indicator". When scoring/spotting part of your duty is to observe the shooter and watch for safety issues like a squib load. The weird part for me was shooting on someone elses schedule. If y'all score each shot the scorer should tell the shooter the shot value as a way to verify the scorig. You can put a small mark in the scoring box when the shot is fired, then write the score after the target is scored. I like to use a block or case holder with the 22 rounds in it as an easy way to keep track of round count. I only have the 22 rounds readily accessible. It is OK to tell shot value & round number. You shouldn't tell round location or coach. You can say 9, not 9 @ 3 O'clock or say wind is picking up. But, go by what the guys running the match say.

Congratulations for going out and doing it. I try to get guys to go but many won't go and shoot a match. F-Class is great for getting on the line without need too much equipment.

I hope you really enjoy it and do well. Update us if you can.

Later,
WNTFW

Jasper1573
January 18, 2011, 07:45 AM
I'll likely put out a post on it once it is done. I am shooting in both F/TR and F/Open that day because I want to shoot as much as I can at 500. I am driving about an hour and a half, so I want to get as much bang for my effort as I can (pun intended);-) Thanks for all of your advice.

Jasper

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