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Discussion Starter #1
Last year I sighted in my 30-06 rifle with 180gr Remington Core Locks at 100 yards and had good groups. A couple of weeks ago while shooting I shot 150gr Remington Core Locks at 100 yards and the area on the target I was hitting was atleat 12" below the bullseye. My question is, would 150gr bullets drop that much at 100 yards compared to 180gr?.......
 

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It's not that the 150 is dropping more, it's that it's not rising as much as the 180. The 180 is harder recoiling and slower moving, this means the barrel rises more before the bullet leaves it.
 

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The difference in Muzzle velocity between the 150gr. and the 180gr. is only 200fps. I doubt if that's why your getting a 12" drop at 100 yards between bullets.

Tell me, this year when you are shooting the 150gr. core-locks, are you also shooting any 180gr. core-locks to see where they are coming in at?

Sw
 

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Rifle barrels handle different bullets and different loads differently. You can't expect two different loadings to shoot the same POI, it's just the way it is. Sometimes you get lucky and they will shoot close to each other, but you can't expect it. Sight in with the cartridge you plan to hunt with and stick with it.
 

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tundragriz said:
It's not that the 150 is dropping more, it's that it's not rising as much as the 180. The 180 is harder recoiling and slower moving, this means the barrel rises more before the bullet leaves it.
tundragriz is spot on.
 

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tundragriz said:
The 180 is harder recoiling and slower moving, this means the barrel rises more before the bullet leaves it.
I agree with this to a certain extent...But to make a 12" difference?....C'mon!.....This rifle just happens to throw the 150gr. bullet at a different spot, unrelated to "drop", or recoil.Some rifles will throw a different bullet to the side, some higher, some lower...This particular rifle throws them low...Real low.
 

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Big Ken said:
tundragriz said:
The 180 is harder recoiling and slower moving, this means the barrel rises more before the bullet leaves it.
I agree with this to a certain extent...But to make a 12" difference?....C'mon!.....This rifle just happens to throw the 150gr. bullet at a different spot, unrelated to "drop", or recoil.Some rifles will throw a different bullet to the side, some higher, some lower...This particular rifle throws them low...Real low.
I was just thinking the same thing while I was outside getting some air. 12" does seem a bit much after thinking about it for a moment.
 

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If your muzzle is moving that much under recoil then its Red Ryder time


A 12 inch difference means that his rifle shoots those bullets lower.

The daughters 30-30 with the reduced load I worked up for her, will throw 2 separate groups 6 inches apart, with everything the same except primers. If you are zeroed with Winchester, Remington will hit low and a little left by about 6 inches. Rifles are finicky critters. They like to eat what they like to eat.
 

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Discussion Starter #9
Sethwood said:
The difference in Muzzle velocity between the 150gr. and the 180gr. is only 200fps. I doubt if that's why your getting a 12" drop at 100 yards between bullets.

Tell me, this year when you are shooting the 150gr. core-locks, are you also shooting any 180gr. core-locks to see where they are coming in at?

Sw
Nope, the 150's were all I had on me at the time. I am going to use a bore sighter to atleast see if my scope is off then I'll go from there. I know this is all "Last Minute" but I have been super busy, hopefully Ill head out to my buddies range tomorrow.......
 

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I shoot 150 gr winchester ballistic tips 1 " high at a hundred and they group a pattern that I can cover with a nickel. If I shoot my bench loaded 150 gr nosler ballistic tips they will group 1/2 high and 2 inches left and I can still cover them with a nickel. Same grain same gun completely differnt pattern. I am not suprised by what you found with 30 grain difference in bullet choice.
 

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G2CDeer said:
Sethwood said:
The difference in Muzzle velocity between the 150gr. and the 180gr. is only 200fps. I doubt if that's why your getting a 12" drop at 100 yards between bullets.

Tell me, this year when you are shooting the 150gr. core-locks, are you also shooting any 180gr. core-locks to see where they are coming in at?

Sw
Nope, the 150's were all I had on me at the time. I am going to use a bore sighter to atleast see if my scope is off then I'll go from there. I know this is all "Last Minute" but I have been super busy, hopefully Ill head out to my buddies range tomorrow.......
For as much lead\copper & copper plated lead as I shoot in a year, I'm gonna stick my neck out here and say that since his rifle has been sitting in a safe or a closet all year long, I'm bettin that the scope has gotton knocked off from last years settings.

I shoot several different calibers of rifles. When I change bullets, either from one manufacturer to another, or from one weight to another even with the same manufacturer, I will get different POI using the same POA.

Other times. I will get virtually the same POI using the same POA with the same manufacturer bullets, but with grain weights from 50 to 80. (I had a ProHunter in .243 that would move the POI maybe 1\4" from a 50gr. Nosler to an 80gr. Nosler when loaded over H-414. Just one of those things)

But a 12" drop is too significant for just the bullet. It has to be that the scope was bumped.

MHO

SW
 

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The 12" was irrelevant to my response, I was responding to the statement that 150s were "dropping" compared to 180s. Within the constraints of using equivalent factory ammunition and limiting to 100 yds, a 150 is going to get there faster and WILL NOT drop as compared to a 180 that is going slower. Aerodynamic factors will eventual reverse that at longer ranges but not at 100yds. But then why a lower impact point.

Recoil has various components, force and speed in both a horizontal and vertical direction. Many factors affect the degree of these forces. Most force is horizontally rearward. At a minimum the vertical component is dependent on resting forces against the barrel or foreend (offhand with grip, soft bags, hard rock, etc), length/weight of the barrel, position of the barrel in relation to the pivot point (stock shape). The pivot point is approximately on the rear of the shoulder. Just for reference, to account for 12" POI difference at 100 would require about 0.1 inch of barrel tip difference given approx sporting gun dimensions.

You have lock time for trigger movement, sear disengagement, and firing pin movement. Then "dwell" (primer ignition, main charge ignition, bullet obturation, travel time down barrel) begins. Dwell also initiates felt recoil. Good numbers to use for dwell on a sporting arm, dwell lasts about 25msec (from igniton till bullet clears barrel)and you will a have about 3/8" of rearward recoil movement.

Now apply this to the data from an 06 150 vs 180 on an 8 lb rifle.

Weight - Recoil Force - Recoil velocity
[email protected] - 17.6 ftlb - 11.9fps
[email protected] - 20.3 ftlb - 12.8fps

Does it account for 12"? don't know, don't care, too many unknown factors in the vertical component. But it does explain why it "appears" that a 150 "drops" more than a 180 at 100yds. There is about 20% more recoil force moving about 10% faster, more recoil moving faster with a slower bullet in the barrel means more barrel lift during dwell.

Anyone shooting handguns experiences this in a big way as all the factors are exagerrated. Bigger bullets mean more barrel rotation.

Enough on this, I have a life.
 

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lol. 12" is a lil extreme for barrel harmonics at 100 yds. i'd start by tightening up the nut behind the trigger first.
tundragriz said:
The 12" was irrelevant to my response, I was responding to the statement that 150s were "dropping" compared to 180s. Within the constraints of using equivalent factory ammunition and limiting to 100 yds, a 150 is going to get there faster and WILL NOT drop as compared to a 180 that is going slower. Aerodynamic factors will eventual reverse that at longer ranges but not at 100yds. But then why a lower impact point.

Recoil has various components, force and speed in both a horizontal and vertical direction. Many factors affect the degree of these forces. Most force is horizontally rearward. At a minimum the vertical component is dependent on resting forces against the barrel or foreend (offhand with grip, soft bags, hard rock, etc), length/weight of the barrel, position of the barrel in relation to the pivot point (stock shape). The pivot point is approximately on the rear of the shoulder. Just for reference, to account for 12" POI difference at 100 would require about 0.1 inch of barrel tip difference given approx sporting gun dimensions.

You have lock time for trigger movement, sear disengagement, and firing pin movement. Then "dwell" (primer ignition, main charge ignition, bullet obturation, travel time down barrel) begins. Dwell also initiates felt recoil. Good numbers to use for dwell on a sporting arm, dwell lasts about 25msec (from igniton till bullet clears barrel)and you will a have about 3/8" of rearward recoil movement.

Now apply this to the data from an 06 150 vs 180 on an 8 lb rifle.

Weight - Recoil Force - Recoil velocity
[email protected] - 17.6 ftlb - 11.9fps
[email protected] - 20.3 ftlb - 12.8fps

Does it account for 12"? don't know, don't care, too many unknown factors in the vertical component. But it does explain why it "appears" that a 150 "drops" more than a 180 at 100yds. There is about 20% more recoil force moving about 10% faster, more recoil moving faster with a slower bullet in the barrel means more barrel lift during dwell.

Anyone shooting handguns experiences this in a big way as all the factors are exagerrated. Bigger bullets mean more barrel rotation.

Enough on this, I have a life.
 

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yukon375 said:
lol. 12" is a lil extreme for barrel harmonics at 100 yds. i'd start by tightening up the nut behind the trigger first.That's the best advice I've seen on this post yet. You got a pipe wrench?
 

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Discussion Starter #15
Well, got the gun bore sighted last night and the scope was wayyyyy off, I mean wayyyyy off. I am going to the range today to throw a couple of shells down range just to make sure everything is in top working condition.......
 

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yukon375 said:
lol. 12" is a lil extreme for barrel harmonics at 100 yds....
The 12" was irrelevant to my response...,
Some are just a little denser than others. YET AGAIN I will say it, my post was not about 12" (can you actually see that in my last point). The post is that a 150 is not dropping a greater amount than a 180 at 100yd as was implied by the OP, not 1 inch not 12 inches. Barrel harmonics is yet another totally distinct issue from dwell and wasn't even mentioned in my post. Or did you somehow see it in there?

Ignorance is bliss to some I guess.

Harmonics: Barrels vibrate under the shock of firing. These vibrations can be minimized or tuned to minimize their impact on accuracy. Generally the harmonic effects are proportional to the square of the barrel length, and so are generally only of concern in rifles but not handguns.
Bullet dwell timeThe bullet dwell time is the time between cartridge ignition, and the time the bullet leaves the barrel. Like lock time, dwell time is a window for error, and can be minimized with a faster bullet or a shorter barrel.
 

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G2CDeer said:
Last year I sighted in my 30-06 rifle with 180gr Remington Core Locks at 100 yards and had good groups. A couple of weeks ago while shooting I shot 150gr Remington Core Locks at 100 yards and the area on the target I was hitting was atleat 12" below the bullseye. My question is, would 150gr bullets drop that much at 100 yards compared to 180gr?.......
Shoot both bullets on the same day. You cant compare it to last year. To many variables like temp, wind, stock presure, scope moving , ect. As others have said sometimes differnt ammo shoots to the same POA sometimes it doesnt.

Good luck, Tony
 

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dooood, get a clue. i guess common sense issent so common.
tundragriz said:
yukon375 said:
lol. 12" is a lil extreme for barrel harmonics at 100 yds....
The 12" was irrelevant to my response...,
Some are just a little denser than others. YET AGAIN I will say it, my post was not about 12" (can you actually see that in my last point). The post is that a 150 is not dropping a greater amount than a 180 at 100yd as was implied by the OP, not 1 inch not 12 inches. Barrel harmonics is yet another totally distinct issue from dwell and wasn't even mentioned in my post. Or did you somehow see it in there?

Ignorance is bliss to some I guess.

Harmonics: Barrels vibrate under the shock of firing. These vibrations can be minimized or tuned to minimize their impact on accuracy. Generally the harmonic effects are proportional to the square of the barrel length, and so are generally only of concern in rifles but not handguns.
Bullet dwell timeThe bullet dwell time is the time between cartridge ignition, and the time the bullet leaves the barrel. Like lock time, dwell time is a window for error, and can be minimized with a faster bullet or a shorter barrel.
 
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