Question about .308 bullet weights and trajectory

K

King_Catfish

New member
Hi everyone,

I was wondering if someone could answer this for me: I hunt with a TC Encore in .308 (15" barrel). I use 150 gr bullets for deer. I would like to use this pistol for black bear as well, and think I should use the 180-gr bullets for this.

Anyway, will my zero change with the heavier bullet? Is ther enough of a difference in trajectory that I will need to sight in again between bear and deer season?

If it helps, I never take any shot over 200 yds with this weapon. With the 150-gr rounds, I zero an inch high at 100 yds.

Thanks!
 
Yes, Most likely it will change zero. You will have to check it to see how much. This may sound strange but, while the 180 grain bullet will be going slower than the 150 it will hit higher with the same scope setting. That has been my experience when changing to a heavier bullet.
 
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Welcome to the board.

Sight-in will change when you change bullet weights. How much depends on lots of factors. You will just have to shoot it to see.
 
So if I use premium bullets, such as the Federal Vital-Shoks or the "Bear Claw" rounds (can't remember the name offhand), I can stay with 150 grains (assuming proper shot placement)?
 
I cant answer the question as to whether you can a 150 gr bullet is good for bear. have never hunted them. I can tell you that any time you change to a different bullet you will have to resight. The reason I said earlier that the 180 would prob group higher than the 150 from the same scope adjustment is this. You are shooting a pistol. If you were shooting a rifle It would be different. All firearms begin to recoil at powder ignition. The pistol begins to rear up. The slower heavier bullet will exit the barrel later into the recoil than the faster lighter bullet. Thus striking higher. This has been my experience with the contenders. But you will still have to resight the gun. If you are concerned with the 150 for bear, why not go to the 165 for both. . You didnt mention if you reload. If not get a box of Federal Premium ammo with the 165 Partition bullet. This load will shoot through elk and will expand on coyotes. It can be shot at both deer and bear with excellent results.
 
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Thanks, I will do that. All replies greatly appreciated.

You are right, I do not reload, but I would like to get into that one day. Do not have the time just now.... perhaps soon.
 
The way I look at it---
Since you didn't say how fast your bullet is with the 150gr slug, I looked in the Sierra reloading book and found that for single shot pistols a 150 gr 308 round should move out at about 2300fps +/- 100--& an 180 gr 308 round should move out at about 2100fps+/-.

If your 1" high at 100 yards now, which is a zero point of about 140 yds, and you change to a 180 slug moving about 2100 fps, you'll have to hold about 1/2" higher at 100 yds to maintain the same zero point with the heavier bullet.

Since your target on either bear or deer is about the size of a 6" pie plate, if you stay within your 200 yd limit, you'll need very little if any sight adjustment to hit your target with either round.
 


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