I have a friend that has a P1 Schmidt and Bender scope that was calibrated for a 300 Win Mag 180 grn bullet and he wants to shoot a 190 grn bullet. I worked out the velocity to get the load to match his drops for the scope. Now that I have matched the scope drop, the load is not the most accurate.

Will changing powder wieight say .3 grns help tighten up the groups? If I go much more I am afraid I will loose the desired trajectory.

Will bullet seating depth help effect group size that much? I am seating now to standard COL.

I am getting a 1.5 to 2 MOA depending on distance. If the increase and bullet seating can get me 1 MOA, I think he will be happy. Sad thing is this gun, with the right laod, is a tack driver.

I suggested he get the best load and have a reticule built to match his drops.

Some rifles just don't like some bullet/powder combos/ You can try varying seating depth, but you may want to try another powder in the same burn range. I had this w/ my 280, shot ok w/ Rl22, but when I went to IMR728, it became a submoa rig.

How much variance in the 2 trajectories?
Is it enough to really matter?
Can you dial in, say, 1MOA high at 100 and bring the down range trajectory back into line? IE if your 1MOA high at 100, will 400 match up, with the intermedeate ranges being slightly high, and the further ranges being slightly low?
Different bullet type available? IOW match both the velocity AND the BC with what it was set up for.

I would find what the rifle likes best at around 300 yards. Then test it closer and farther away against the scope's settings....I think you will find it within and acceptable range of variance.

Watch out for the tendency to shoot at 100 yards and assume you know all about what's going on at long range.....or all your careful planning may be wasted.

Cheers,

Dan

I would work up the most accurate load with the bullet of his choice. Then I would sight the rifle in at the exact range he feels is the most important.

When using a BDC scope longer range is usually better.

[ I like and use several different BDC scopes].

Say you sight in at 600 yards, with the scope on "6".

Then shoot at the other ranges to see if any adjustment is necessary. If your load is flatter you might, say for instance, when shooting at 300 yards set the scope on "3" then move down a minute, to have a "perfect" 300 yard zero.

And remember this, usually in the field [as opposed to the target range] the distance is usually never exactly in hundred yard increments, or on level ground, so unless you load is drastically different than the 180gr Cam it is not that big of a deal.

In fact at distances farther than 300 yards your point of impact can easily vairy a minute of angle due to temperature and other weather conditions.

Well, showed my friend the test target and explained what I thought might help reduce group size. I am going to lighten trigger pull and increase .3 grns. After i lighten trigger pull I will shoot the load I have then another .3 grns more to see if there is a significant difference. If I go hotter He may need to adjust for the 100 and 200 shots and be close for the longer ranges. Ramge time will tell, will see what happens next weekend.

Thanks for all the replys.

Why does he want to go to a 190 grain bullet? Personally, if the scope is calibrated for a 180 grain bullet, I'd stay with that. 10 grains more can't make that much difference.

I have loaded a lot to match specific trajectorys 50 fps deferants isn't going to make a bit of differants.

quote:

Originally posted by Harold R. Stephens:
I have a friend that has a P1 Schmidt and Bender scope that was calibrated for a 300 Win Mag 180 grn bullet... I suggested he get the best load and have a reticule built to match his drops.

Hey Harold, I'd suggest that the original Calibrated Reticle was not nearly as accurate as a person would imagine. Too many Variables involved in the shooting cycle for it to be accurate at all Altitudes, Temperatures, Bore Changes, and Lot-to-Lot variances in the Cartridge Components.

Get a good accurate Load, adjust it to hit Zero at a distance 100yds "short" of his MAX desired shooting distance and then see how close the other Reticle markers align. If he sighted in Dead-On at 300yds(I mean shooting not a computer generated Trajectory) and then check the 200yd and 400yds Points of Impact, they should be close enough that it doesn't make a clinton. Or, he could always make a Drop Chart to fit the new Trajectory with the current Reticle.

Even if he gets a new Custom Reticle, the normal Varances listed above will prevent it from being accurate over a period of time.

I do not mean this mean spirited when I say Custom Drop Rate Reticles are another PT Barnum style trick being pulled on folks who do not understand that Loads and Barrels constantly change.

Best of luck with the new Load.

quote:

Originally posted by Hot Core:


I do not mean this mean spirited when I say Custom Drop Rate Reticles are another PT Barnum style trick being pulled on folks who do not understand that Loads and Barrels constantly change.

Hey HC, you have a natural talent for

Loads and barrels constantly change whether you have a ballistic reticle or not. The same change that makes a 3" difference at 450 yards with a ballistic reticle will make a 3" difference with a regular plex reticle. The real difference is that with the ballistic plex reticle you won't have to guess where to hold as opposed to guessing how far 26" or so is above where you want your POI with the regular reticle.

I guess I've been PT Barnumed 5 times now and I find it much more difficult to shoot acceptable groups at the longer ranges with a regular old fogey type of plex.

quote:

Originally posted by woods:
...I guess I've been PT Barnumed 5 times now and I find it much more difficult to shoot acceptable groups at the longer ranges with a regular old fogey type of plex.

Now who do you think you are foolin'??? You've been PT Barnumed waaaaay more than that on "Thingys" alone.

Huuuum, I'd guess you never heard of folks "Crankin' In Windage and Elevation" l-o-n-g before the Boutique(PT Barnum) Reticles became popular.

If a person wants to shoot at distance, the very best thing going is still the old style Mil-Dot Reticles which allow infinite adjustment and variability. Harold's buddy can use some of the simple logic from that link to set his current Reticle for excellent use as well - if he wants to - and not change a thing inside the scope. However the 100yds picket might be 106yds and 200yds might be 211yds. I can see where that would create a lot of confusion for a "Thingy" man.
-----

Or he can get the very best and most accurate load possible using the never-improved-upon Creighton Audette Method, actually shoot the groups at distance to see where they hit and send the scope in for a new Boutique Reticle. And of course do that everytime he changes Bullets or Powders, or as the Bore changes. No doubt it will help the economy. And if that is what he wants to do, I'm all for it.

As far as "cranking in elevation" goes that works OK if you have the time and don't lose your place. Sorta follow this sequence

Mil-dots are OK as long as you have your calculator with you or don't get confused at exactly the wrong time and hesitate while thinking about it.

Hey HC, I have an idea. Why don't you write a book about all the ways you do stuff. You could call it
DUCT TAPE & BALING WIRE; The Way We Old Fogeys Used to Reload and Shoot

quote:

Originally posted by woods:
As far as "cranking in elevation" goes that works OK if you have the time and don't lose your place.

I always love it when Woods makes an excellent point. Darn shame he didn't do it here. I can see where going from "0" to the number "22" would create confusion for the folks who rely on their fingers and toes to keep count.

quote:

Sorta follow this sequence Mil-dots are OK as long as you have your calculator with you or don't get confused at exactly the wrong time and hesitate while thinking about it.

Amazing how that slight mod completely fixed that sentence.

quote:

Hey HC, I have an idea. Why don't you write a book about all the ways you do stuff. You could call it
DUCT TAPE & BALING WIRE; The Way We Old Fogeys Used to Reload and Shoot

That is a catchy title. Hope to change the "Used to" portion this week to "still".

quote:

Originally posted by fredj338:
Some rifles just don't like some bullet/powder combos/ You can try varying seating depth, but you may want to try another powder in the same burn range. I had this w/ my 280, shot ok w/ Rl22, but when I went to IMR728, it became a submoa rig.

+1. I could be full of beans (happens all the time) but I believe I felt something different in recoil between RL22 and IMR7828 in my 7mm magnum, loads that were by-the-book similar. Accuracy wasn't much different but the RL22 rounds just grated on my nerves...

How close does it have to be, for hunting use? I am not sure I'd be anxious to change much for a 5% change in bullet weight. I can't see much difference between 140 grains and 145 grains, didn't obsess over that very long at all.

Hey Harold

Here is the pic of the S & B P-1 reticle

quote:

P-1 (Bryant) reticle
The P-1 Reticle was developed for Schmidt & Bender by Deputy Sheriff Robert Bryant, who has many years of experience as a SWAT team member and advisor to police departments. You will find the Bryant design very user-friendly and exceptionally efficient in high stress situations.

The horizontal lines under the crosshair make it possible to estimate distances up to 500 yards by cradling an 18" object between them. The posts, lines and the circle are all proportioned to help in rangefinding and in making allowances for wind or movement. Complete details are included with the scope.

So if the horizontal lines at the bottom are for rangefinding, how is he matching the reticle to a trajectory?

Now with the Zeiss RapidZ 800 I have on my 6.5 rem mag



shooting a 140 gr Sierra Game King at 3100 fps when zeroed at 200 yards and setting the power at 12, the trajectory matches like this

296 yds
398 yds
499 yds
600 yds
702 yds
803 yds

Now HC, tell me how that is not more useful than a Mil-Dot

quote:

Originally posted by woods:
...shooting a 140 gr Sierra Game King at 3100 fps when zeroed at 200 yards and setting the power at 12, the trajectory matches like this

296 yds
398 yds
499 yds
600 yds
702 yds
803 yds

Now HC, tell me how that is not more useful than a Mil-Dot

At great risk of totally confusing Woods(more) , I was talking about actually Shooting a firearm to see where the Bullets Impact and then create a Drop Chart specific to the Reticle. I hope no one else thought I was talking about a Computer Generated Trajectory which can be way, waaaaaaaaaaaaay off.
-----

Now for Woods, After due consideration, I believe your Boutique Reticle will do fine for you inside 29.843yds.

Wood, that does not look like the reticle on his rifle.

Sorry his scope is a Shepperd scope.

Not to get in the way of Woods and Hot Cores pissing match, I have pretty much matched the trajectory and with a little seating depth adjustment, I think he will be good to go with the new load. 4" groups today at 400 yards. Trigger adjustment was a bid help, got it as light as it will go without cutting the spring or replacing the trigger.

I personnaly think this was a futile effort, but that was what he wanted and I learned a few things along the way and got some trigger time and wind reading practice on his dime. Right or wrong by other peoples standards is irealavant, this was his gun and his load and I agreed to help him. In the end he will be the sole judge of whether it was the right or wrong thing to do.

quote:

Originally posted by Hot Core:
a Computer Generated Trajectory which can be way, waaaaaaaaaaaaay off.

Works for me


just have to work on windage some.

The thing I like about a BDC cam is that I can lazer an animal, dial in the "UP, dial in or hold off for the windage, and shoot.

True the trajectory of your ammo must match the BDC but aht is not hard to do.

I have taken javelina with a 308 at 412 yards with a 4x BDC scope,first shot hit/kill, a red fox at @325, estimated, one shot one kill, elk at 350 yards, estimated, and an antelope at a little over 550 yards, all using the BDC feature of the scope on the rifle.

Mill Dot and Custom or factory Ballistic Reticles work too, and work very well, IF you take time to learn them. I have used them as also.

These methods and "tools" work much better than just trying to hold over IMHO, especially after the first shot is fired and the animal might be moving.

Hey Woods, It appears you left the " . " out from between the Zeros - 30.0yds!

Did BH shoot that group for you with one of his excellent rifles?

quote:

Originally posted by Hot Core:
Hey Woods, It appears you left the " . " out from between the Zeros - 30.0yds!

Did BH shoot that group for you with one of his excellent rifles?

Jealousy, it's a pitiful thing!

Yes it is! Nice shooting.

No telling what all you got "cranked in" to even hit the target.
-----

Hey Harold, Did you ever get it shooting close enough that your buddy will be happy without needing to change the Reticle? Your post above indicates it is shooting pretty good.

Hey Woods, Couple of questions for you:

1. Were you aiming at that Target?

2. Did it take 40 or 50 shots to flinch that many close together?

Gentlemen

At long range, whether you "dial up" or use a Mil Dot, or Ballistic Plex reticle it gives you a devinate or at least a more definate hold than just holding up with a conventioinsl reticle.

Takes a lot more of the "guess out of it".

While not as critical for the first shot, maybe, it makes a big difference on follow up shots, especially if the game is moving IMHO.