30-06 150 vs 180gr trajectory
02-01-2010, 06:15 PM
#11
Spike
Thread Starter
Join Date: Mar 2008
Posts: 73
I know if I were to shoot 150 gr. rounds I'd need to sight my scope for such round at impact, but this was an experiment comparing a known impact (180 gr) vs. an unknown impact(150 gr) and not changing any other variable; save manufacturers. I was just suprised at the elevation difference between the two weights.
I cannot say my rifle dislikes this rem. core-loks b/c my 3 shot group was 5" high with the 1st and 3rd making a figure 8 (down left to right) and the second 1/8" dead low the 1st; the group looks like a "greater than sign" on the center vertical line of the target.
ridgerunner, LOVED the explaination on harmonics concerning a barrel and the round fired. I knew about this but failed to take this into consideration when I asked the question. Thanks again.
littlekid
I cannot say my rifle dislikes this rem. core-loks b/c my 3 shot group was 5" high with the 1st and 3rd making a figure 8 (down left to right) and the second 1/8" dead low the 1st; the group looks like a "greater than sign" on the center vertical line of the target.
ridgerunner, LOVED the explaination on harmonics concerning a barrel and the round fired. I knew about this but failed to take this into consideration when I asked the question. Thanks again.
littlekid
02-05-2010, 03:02 PM
#12
Spike
Thread Starter
Join Date: Mar 2008
Posts: 73
WillC,
Your post has risen a question. To preface my question, I've always shot 180gr Federal Premium ammo, of varying designs (i.e. boattail, Nosler Partrition, etc) for the past 10+ yrs since I bought this rifle and have always gotten subinch groups @ 100yds.
My question is...if I re-zero my scope for point of impact with 150gr Rem core-loks and still achieve subinch groups @ 100 yds in the 10 ring, do I still say my rifle does not like this round?
Your post has risen a question. To preface my question, I've always shot 180gr Federal Premium ammo, of varying designs (i.e. boattail, Nosler Partrition, etc) for the past 10+ yrs since I bought this rifle and have always gotten subinch groups @ 100yds.
My question is...if I re-zero my scope for point of impact with 150gr Rem core-loks and still achieve subinch groups @ 100 yds in the 10 ring, do I still say my rifle does not like this round?
02-07-2010, 10:03 AM
#13
Spike
Thread Starter
Join Date: Mar 2008
Posts: 73
WillC,
Your post has risen a question. To preface my question, I've always shot 180gr Federal Premium ammo, of varying designs (i.e. boattail, Nosler Partrition, etc) for the past 10+ yrs since I bought this rifle and have always gotten subinch groups @ 100yds.
My question is...if I re-zero my scope for point of impact with 150gr Rem core-loks and still achieve subinch groups @ 100 yds in the 10 ring, do I still say my rifle does not like this round?
Your post has risen a question. To preface my question, I've always shot 180gr Federal Premium ammo, of varying designs (i.e. boattail, Nosler Partrition, etc) for the past 10+ yrs since I bought this rifle and have always gotten subinch groups @ 100yds.
My question is...if I re-zero my scope for point of impact with 150gr Rem core-loks and still achieve subinch groups @ 100 yds in the 10 ring, do I still say my rifle does not like this round?
02-07-2010, 11:19 AM
#14
Spike
Thread Starter
Join Date: Mar 2008
Posts: 73
Yea I know, it was a dumb question; but I was hoping WillC would expound further on his reasoning as to why I should consider this a "bad" round for my rifle. If all things being equal (powder charge, etc.), a lighter round should have less drop (i.e. POI) due to its smaller mass. In other words, Newton's Law of Universal Gravitation.
02-07-2010, 07:47 PM
#16
Boone & Crockett
Join Date: Feb 2003
Posts: 10,679
It doesn't have anything to do with anything other than it being a different load and your barrel "vibrating" differently as the bullet and gasses travel down the barrel.
This is 100% on the money. Ideally the bullet will exit the barrel at the same time the barrel stops movement in one direction and before it begins movement in the other direction. If your bullet is exiting the barrel when the muzzle is stopped your "load" will be "accurate" If your bullet is exiting the barrel when the muzzle is moving it will tend to "throw" bullets.
It isn't "recoil pulse" like some banned dolt stated. If that were the case the heavier bullet would impact higher at 100 yards than the lighter weight bullet did due to the heavier bullet generating more recoil which creates more vertical barrel / rifle movement and the bullet remaining in the barrel for a longer period of time.
Your rifle just shoots the 150 core lokts to a different point of impact. Just because it shoots to a different POI does not mean that your rifle doesn't "like" that particular load.
Shoot groups to see if your rifle likes the 150CL's. If it doesn't group then your rifle doesn't like them. If you get sub MOA groups like you do with your other loads then you are good to go. You just have to adjust your scope if you want to shoot them.
When you pull the trigger the pressure behind the bullet creates a vibration of the barrel, some say the muzzle moves in a circle some say a figure 8 but it does move, now depending on the pressure and the velocity is what determines where the muzzle is in its harmonic travel when the bullet exits the barrel. This is what determines the POI with different bullets. this also determines how your rifle will group, if the bullet exits the same time, same place in the harmonic travel at the same velocity then the bullets all land in the same place on the target (if you do your part).
You can dramaticly change group size by something as simple as seating dept as that changes where in the harmonic travel the bullet exits the muzzle.
RR
You can dramaticly change group size by something as simple as seating dept as that changes where in the harmonic travel the bullet exits the muzzle.
RR
It isn't "recoil pulse" like some banned dolt stated. If that were the case the heavier bullet would impact higher at 100 yards than the lighter weight bullet did due to the heavier bullet generating more recoil which creates more vertical barrel / rifle movement and the bullet remaining in the barrel for a longer period of time.
Your rifle just shoots the 150 core lokts to a different point of impact. Just because it shoots to a different POI does not mean that your rifle doesn't "like" that particular load.
Shoot groups to see if your rifle likes the 150CL's. If it doesn't group then your rifle doesn't like them. If you get sub MOA groups like you do with your other loads then you are good to go. You just have to adjust your scope if you want to shoot them.
Last edited by bigbulls; 02-07-2010 at 07:56 PM.
02-09-2010, 02:28 PM
#17
Boone & Crockett
Join Date: Jan 2004
Location: Eastern PA
Posts: 12,746
Besides barrel harmonics you have way too many vaiables here - totally different bullet design, different propellents, manufacturing processes, velocity, just to name a few.
If your rifle shoots both loads well, pick one and sight in for in. If you change a load, you should resight again. Normally, all else being equal, the 180 gr 30 cal is ballistically superior to the design in the 150 gr.
If your rifle shoots both loads well, pick one and sight in for in. If you change a load, you should resight again. Normally, all else being equal, the 180 gr 30 cal is ballistically superior to the design in the 150 gr.
