68/69 versus 75/77's for longer ranges

[Powerlock25]

shooting from 16" and 18" barrels (both 1 in 7", WOA) is it more ideal to use 68/69gr or 75/77gr bullets

many 400-500+ yard shots

My range goes out to 750yds but that may be too far for this gun

any thoughts appreciated!

 

[sinister]

Re: 68/69 versus 75/77's for longer ranges

69-grain Sierra Match Kings will shoot tighter than 77s at 200 and 300 yards, but 73s, 75s, and 77s will not drift as far in any kind of wind (3 mph and up) at 300 and beyond.

69s are outstanding bullets (I haven't shot 68s), but you've got to be on top of your wind calls.

 

[Grump]

Re: 68/69 versus 75/77's for longer ranges

Yup, calling the wind is key.

*IF* your rifle shoots noticeably tighter with the lighter ones, use them and you'll be okay IF you are good with the wind.

Me, I was spoiled growing up with .30-06 and .308, so I really prefer the wind-bucking traits of the 77s. I'd rather shoot a reliable 1 MOA @600yd rifle with those, than a 1/2 MOA rifle with 68-69s.

 

[Powerlock25]

Re: 68/69 versus 75/77's for longer ranges

what is the distance that the 69's start to give up?

 

[Grump]

Re: 68/69 versus 75/77's for longer ranges

Define "start to give up".

I've wandered away from discussions where someone was fretting over a 0.5 MOA difference (2 clicks on a regular scope) in wind correction needed at 600 yards. That's about three inches. Stick the typical shot dispersion "cloud" around the theoretical centers of the groups, and you have some seriously overlapping circles of likely dispersion.

 

[Powerlock25]

Re: 68/69 versus 75/77's for longer ranges

What distance can I shoot either of these bullets and not expect the groups to blow up? Obviously wind must be taken into account.

Seems like some of these guys at the range try to stretch their 223's out to distances like 700yds+ - It drives me crazy trying to find the impact while working the pit for them.

 

[shoot4fun]

Re: 68/69 versus 75/77's for longer ranges

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DDS260</div><div class="ubbcode-body">What distance can I shoot either of these bullets and not expect the groups to blow up? Obviously wind must be taken into account.

Seems like some of these guys at the range try to stretch their 223's out to distances like 700yds+ - It drives me crazy trying to find the impact while working the pit for them. </div></div>

I've seen the 223 shot expertly at 1000 yards. Not by me, yet.
I would say you need to shoot your rifle with all bullets in question here and decide for yourself. But, I think you will find 75/77's better at long distances. I do assume you will be using 1 in 8 or faster twist.

 

[RODENT]

Re: 68/69 versus 75/77's for longer ranges

I shoot my 20" LTR out to 950 with 69gr SMKs at 12" plates. Reading the wind is key obviously. I push them around 2950. No experience with them in an AR.

 

[427Cobra]

Re: 68/69 versus 75/77's for longer ranges

Go Heavy!

 

[Powerlock25]

Re: 68/69 versus 75/77's for longer ranges

will do, I have been really hoping that I could get the 75's to work out since they are cheaper than the 77s

still waiting for the 69's and 77s to arrive in the mail, so we will see

 

[k2peaker]

Re: 68/69 versus 75/77's for longer ranges

In an 18" AR, I've standardized on the 77gr. SMKs. Sure, I've tried the 69s but don't see benefits over the 77s over yardages that I routinely shoot. Cheaper? Aren't we talking marginally cheaper?

Rocky Mtn 3-gun competitor where 425 yds is typical with a couple of matches each year where we go out to 600 yds.
Like others have said, the slightly higher BC gives a bit better wind bucking over the 69s but it's not huge.
If you want a more objective, definitive comparison use the JBM ballistic calculator and do a quick side by side between the two. The 69s and 77s are within the JBM library so it would be a pretty easy comparison to run.
My intuition tells me there would maybe be a .1-.2 mil difference at say 500 yds (@full value). Guess on my part though.
I did shoot a stage last year where we had 2-3 full value cross wind conditions (400+ yds). Just horrible. The 77s helped but not enough.

 

[Jaeger308]

Re: 68/69 versus 75/77's for longer ranges

Have you shot 69s out of the 1:7 barrel? They may spin apart down range depending on your load. I would go with the 77's. I loaded Lapua 77 scenars out of a 1:8 twist for my son this past year for the nationals at Camp Perry, he shot 200,300&600 yard lines with them. He did very well

 

[7.62willdo]

Re: 68/69 versus 75/77's for longer ranges

you should look at the berger 70 the numbers beat all the matchkings.

 

[splean]

Re: 68/69 versus 75/77's for longer ranges

I have tried the 69gr SMK in both my 20" 1-9 and 20" 1-7 AR-15s. In both cases they proved to be very accurate rounds. My local range runs out to 600 yrads and the 69gr SMK got out there. I haven't tried the 77gr SMK yet. I suggest you try them both. Good luck.

 

[Grump]

Re: 68/69 versus 75/77's for longer ranges

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jaeger308</div><div class="ubbcode-body">Have you shot 69s out of the 1:7 barrel? They may spin apart down range depending on your load.</div></div>

I call bullshit Internet myth on this one.

Yeah, I've shot 'em. Actually, the 1:7 Colt HBAR did better with 69s than anything else.

And cheapo 55-gr FMJBTs from Winchester and Hornady never blew up with the 1:7 barrel, either, and they were going even FASTER, up to 3,200 fps. Ordinary copper jackets, not soft iron with copper plating like the cheapo .308 bullets I've used a lot in the past.

 

[shoot4fun]

Re: 68/69 versus 75/77's for longer ranges

Grump really echos my experience. I shoot 55 FMJ PMC thru an AR with 1 in 7 twist. They don't blow up and ringing steel at 400 yds has been no problem. Most bullet blow ups I've seen were traced back to a rough spot in a barrel. I had a bud with a 22-6mm with 1 in 7. It started blowing up bullets. We found a rough spot with the bore scope. Cleaned it up and clovered the barrel. Now it works just fine.

 

[Jaeger308]

Re: 68/69 versus 75/77's for longer ranges

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grump</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jaeger308</div><div class="ubbcode-body">Have you shot 69s out of the 1:7 barrel? They may spin apart down range depending on your load.</div></div>

I call bullshit Internet myth on this one.

Yeah, I've shot 'em. Actually, the 1:7 Colt HBAR did better with 69s than anything else.

And cheapo 55-gr FMJBTs from Winchester and Hornady never blew up with the 1:7 barrel, either, and they were going even FASTER, up to 3,200 fps. Ordinary copper jackets, not soft iron with copper plating like the cheapo .308 bullets I've used a lot in the past. </div></div>

Didn't post that they will? But rather they may? At this years SAFS class at Camp Perry the AMU issued some 1:7 twist barrels out to students and had Hornady 75 gr. spin apart. I was on another range with the Marine team that day and only heard about it?

 

[jmtyndall]

Re: 68/69 versus 75/77's for longer ranges

You likely heard wrong. I can't imagine a 7" twist blowing up anything heavier than 60gr. And the 55gr's that I've heard blowing up were using a really thin jacket, combined with a twist that was on the faster end of the specs. Even then it's not common.

If it did happen, the bullets were either bad, or the bores were tearing up the bullets for an unrelated reason.