# 55gr vs. 75gr (243 cal)



## daruoho (Sep 28, 2006)

I use primarily winchester 55gr silver tips for coyote, but and wondering if I woulden't be better off with 75gr Vmax Moly. I'm just concerned that the 55gr is to lite and would'nt buck the wind at all where as the 75gr will?


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## Danny B (Jun 6, 2006)

daruoho, If you're shooting coyotes at the average ranges of around a 100 yards or so and the 55 gr bullet does the job, why change?

I've killed many a coyote with a 243 before they had 55 gr bullets, I was using 80 gr spitzers and they'd blow BIG holes in coyotes.

I've also killed many coyotes with 55 gr bullets out of 220 swifts and 22-250s, they did the job just fine even in some wind.

As long as you're not making three and four hundred yard shots all the time on real windy days, I see no reason to change. Besides when it gets to windy it's best to stay at home and do honey do's :lol:


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## tubby (Aug 9, 2006)

I sight in 1 inch high at 100 yards with winchester 100gr bullets. I know it's over kill. But it works on white tail deer too  and I don't keep hides.

I have to sight in again when I shoot lighter weigth bullets and I'd shoot them if I had the time to go to the range and wait for an open lane and spend 30 mins to an hour doing it all over again, but I don't.


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## Fallguy (Jan 23, 2004)

I shot those 55 silvertips out of my Ruger .243 and saw great accuracy. But then I switched to 70 grain Nosler BT after hearing good things about the round. Also the 70s come out of my gun a little slower and I was worried about long term effects on my barrel shooting a 4000 + fps bullet out of it. Maybe I didnt' need to worry but I did. I like the Noslers. I think sometime in the next year I am going to switch over to 85 grain Nosler Boat Tailed Hollow Points and try to use this round for both coyotes and deer. Then I don't have to resight in my gun 3 times per year!


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## SDHandgunner (Jun 22, 2004)

OK, I just went to the Winchester & Remington web sites and looked up the published Muzzle Velocities and Ballistic Coefficients for the Winchester 55gr. Ballistic Silvertip, and the Remington 75gr. AccuTip Boat Tail in .243 Winchester.

First the .243 Winchester 55gr. Winchester Ballistic Silvertip
The published muzzle velocity is 3910 FPS, and the published Ballistic Coefficient is .276.

Given these figures I ran this through my Ballistics Program and obtained the following numbers.

55gr. Winchester Ballsitic Silvertip

Trajectory with a 200 yard zero

100 yds. = +.7"
200 yds. = 0
300 yds. = -4.3"
400 yds. = -13.1"
500 yds. = -27.8"

Wind drift in a 10 MPH cross wind

100 yds. = .8"
200 yds. = 3.8"
300 yds. = 7.8"
400 yds. = 14.6"
500 yds. = 24.2"

75gr. Remington AccuTip Boat Tail

Trajectory with a 200 yard zero

100 yds. = +1.1"
200 yds. = 0
300 yds. = -5.6"
400 yds. = -16.8"
500 yds. = -34.9"

Wind drift in a 10 MPH cross wind

100 yds. = .8"
200 yds. = 3.2"
300 yds. = 7.6"
400 yds. = 14.2"
500 yds. = 23.4"

Time of flight enters the picture as well which is a result of Muzzle Velocity and Ballistic Coefficient. There are other variables to consider also, not the least of which in my mind is Sectional Density. Sectional Density is a ratio of a bullets weight vs a bullets diameter (ie a 55gr. .224" & a 55gr. .243" Ballistic Tip Bullet are not created equal and have vastly different ratios of Weight vs Bullet Diameter. Obviously if both bullets are the same weight the one with the larger diameter will have less mass to it per its diameter.

.224" Bullet sectional densities
40gr. = .114
45gr. = .128
50gr. = .142
55gr. = .157
60gr. = .171

.243" Bullet sectional densities
55gr. = .133
58gr. = .140
60gr. = .145
65gr. = .157
70gr. = .169
75gr. = .181
80gr. = .194

To my way of thinking a 55gr. Nosler Ballsitic Tip fired out of a .243 Winchester will likely BLOW UP on a Shoulder and probably cause a nasty wound. On the other hand due to the bullets low sectional deisnty and explosiveness on a perfect broadside shot the bullet may blow up & fragment inside the Coyote and not exit.

On Coyotes about any bullet will work to some degree or another. When we get into the realm of trying to minimize pelt damage the situation gets much trickier and involves a lot of variables. I could probably shoot Coyotes the rest of my life and not know the exact answer.

The bottom line for me is first and foremost I am a huge fan of both the .223 Remington and .243 Winchester cartridges. I guess I have always been impressed by the performance I have obtained with both of these cartridges on game. Next I want to KILL the Coyotes I shoot and do not want to chase a wounded Coyote around the country side, so for the most part pelt damage is secondary to me. You bet if I get a nice pelt that does not have a huge hole in it that is a bonus.

From the numbers above I think you'll see that there is probably less difference in wind drift that you probably imagined as the light weight bullet that is traveling so much faster has less time for the winds effects to act upon the bullet.

Larry


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## jerry hunsley (Jan 20, 2006)

daruoho said:


> I use primarily winchester 55gr silver tips for coyote, but and wondering if I woulden't be better off with 75gr Vmax Moly. I'm just concerned that the 55gr is to lite and would'nt buck the wind at all where as the 75gr will?


I use 70gr. Ballistic tips loaded to 3500fps. and have no problem with exit holes. Just blows up inside.


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## go4thegusto (Sep 29, 2004)

The decision should be made on accuracy. A short 55 grain bullet requires a slow twist barrel 1:12 or more. My encore 243 barrel is 1:10 and shoots the 75 grainers into 3 inches at 200 yards. I moved up to the 95 grain bullets and the groups dropped to 1 inch. The longer bullets need to spin faster to stabilize them.
Accuracy should be the first concern. Speed is overrated. If you study the ballistics you will see that the light bullets start off fast but slow down quickly. By 300 yards or so the heavier bullet will have caught up. Too fast is also too explosive on fur bearers, I sold my 220 swift after blowing fox about in half at close range....and that was back when they were $80!


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