Will 77 grain bullets stabilize in a 1:9 twist barrel?

[charlie b]

LOL yeah I think you are correct. When I look at benchrest competition I see lines of flags from bench to target, and that's for 100 or 200yd, not long range. I did watch them check the wind and sights carefully and then run 10 as fast as they can.

At our range I put up some ribbons at each of the target stands (every 100yd). So, I can at least see the difference along the range. Problem is they are frequently different second to second. Left at 100, right at 300, left again at 500, calm at 800, etc, etc. Next couple of seconds and every thing shifts.

I WILL get better at this!!!! I insist. :) FWIW, I am not competing, except with myself. After I check this one at the longer ranges I will go back to a bipod and rear soft bag. What I like to do is 'plink' at soda cans at 600yd :) I also have two small gongs I sometimes set up (4" and 6") at different target stations to shoot at. The down side is I cannot measure group sizes when I do this, but, it is much more fun to see the cans explode :)

[charlie b]

Had a very good day at the range today, except for my 600yd target :( No wind at all and then it worked up to about 2mph :) This series was all fired from a Harris bipod with a rear bag, my 'normal' shooting setup for this rifle.

At 200yd I fired two fouling shots, then two to check zero. Adjusted windage and then an 8 round group that ended up being 0.9" Not bad for me.

Set to my 600yd dope and fired a shot at my 6" gong. Hit it dead center. Then fired a 5 round group that was horrible, around 10". I did not know how bad until I went and looked at the target. I have no idea what I did, but, it was bad.

I then shot a bunch of 'plinkers'. Soda cans, gong, etc at various ranges from 200 to 600.

Then I decided to try 1000yd. Wind was 1-2mph so it was a perfect day for this. I checked my ballistic calculator and it said 33.5MOA up from my 100yd zero setting. I started turning the turret on my scope, two full turns plus the 3.5. There is a berm with some white rocks on it I can see impacts. So, I fired one. About 2 ft low so moved the setting up and fired again. About 10" high. Down a bit. Hit just to the left of the rock about 6"!! Then fired 15 more rounds at that setting (+36MOA). There was a 12" gong out there so I shot at it. All but 4 rounds hit the gong with the misses just off the left edge by a few inches.

This satisfies me that the 77gn bullet is stable out to 1000yd. Based on bullet drop the muzzle velocity is just under 2700fps (2690?).

It also encourages me to keep shooting at the longer ranges. :)

PS I was also surprised that my scope had enough adjustment range for this as I never checked he specs on it.

[CFJunkie]

That is great information. I am happy to see the 77s maintain their stability out that far.
I post a like but apparently that feature has died with the new server.
Sound like you had some fun testing. That is the most important thing.

[charlie b]

Last post in this thread for me. Had another good day at the range. I also had some of my new Lapua brass loaded up. Same load, 77SMKs, 23.5gn Varget, Rem BR primers. Shooting off a Harris bipod with rear bag.

Shot a group at 200 yd just to warm up a bit. 1.5". Adjusted windage just a bit.

At 600 yd 5 round group was 3.9" Not too bad for me.

Then 1000yd again. The wind was not bad but was swirling, 2-3.5mph. At 1000yd that translates into about 20-30in of windage. Took me 10 shots to get windage and elevation just right. Then yook some shots at a milk jug I had out there. Took me 8 rounds to hit it. Just to the left, just to the right, little low, little high, repeat. Hit it half way up on the right hand side (wind was left to right). I also shot a 10 round group which measured 18". I consider that a success considering the wind being good for 5-10" of that.

Two other guys were shooting a 10" gong at 1000 with their custom chassis 300 Win Mags. They were only hitting every other shot so I didn't feel too bad :)

NO, this is NOT a 1000yd target bullet. BUT, it is stable out that far. I am impressed at how well that little bullet does at range.

PS when it did hit the milk jug full of water it was not impressive. It jumped slightly but no big explosion like at closer ranges.

[TommyD11730]

Having read this thread I thought I too would try 77 TMKS in my 12fv.
For reference my pet load is 69SMKs at 24.6 grains of Varget. Consieved accidentally as they turned out a COAL 2.237 VS the 2.298 I had intended. They shoot very well. Less then .5moa at 100 and under 1 moa at 200.

So today I gave the 77 TMKS a try. With ten thousands jump the COAL is 2.385. Powder was 21.8 and 22.0 varget.

Accuracy at 100 yards was good. Matching my 69s. With only a few rounds left I tried the 77s with 21.8g varget a try. Oh boy, they sank like rocks and the group really opened up.

So I'll load some up at 22.5 next time out.

How did everyone else do when moving out past 100 yards?

[hamiltonkiler]

Having read this thread I thought I too would try 77 TMKS in my 12fv.
For reference my pet load is 69SMKs at 24.6 grains of Varget. Consieved accidentally as they turned out a COAL 2.237 VS the 2.298 I had intended. They shoot very well. Less then .5moa at 100 and under 1 moa at 200.

So today I gave the 77 TMKS a try. With ten thousands jump the COAL is 2.385. Powder was 21.8 and 22.0 varget.

Accuracy at 100 yards was good. Matching my 69s. With only a few rounds left I tried the 77s with 21.8g varget a try. Oh boy, they sank like rocks and the group really opened up.

So I'll load some up at 22.5 next time out.

How did everyone else do when moving out past 100 yards?

I don’t reload. I shoot a standard mk262 mod 1 load. They are still .5moa at 500yds with no wind. 2.5-3” groups all day. Ringing 10” plates at 700yds.


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[charlie b]

FWIW, the above loads were 23.5gn Varget with 77smk in my 22" Axis heavy barrel running 2800fps.

[TommyD11730]

FWIW, the above loads were 23.5gn Varget with 77smk in my 22" Axis heavy barrel running 2800fps.

At a COAL of 2.28?

Looks like I have plenty of headroom in terms of my powder charge.

Thank you sir.

[CFJunkie]

with my 12 FV .223, my best loads are seated at 2.296 to 2.305 C.O.A..L. with the 77 SMKs.
For the 77 TMKs my best loads are seated at 2.339 to 2.342 C.O.A.L.

But my chamber has over 3,000 rounds down the tube.

[hamiltonkiler]

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[charlie b]

At a COAL of 2.28?

Looks like I have plenty of headroom in terms of my powder charge.

Thank you sir.

Yes, at 2.28" oal. That used to be about .020 off the lands, but, that was measured about 1500 rounds ago. :)

[TommyD11730]

FWIW, the above loads were 23.5gn Varget with 77smk in my 22" Axis heavy barrel running 2800fps.

Welp loaded up 20 or so rounds to try out. @ a COAL of 2.285 and 23.5g of Varget quick load says this is nearly @ PMax. A little hotter then I normally like but the velocity is very close to a 69G SMK I nearly shoot.
So, tomorrow Ill send 20 @ that recipe. Think Ill fire them last in case it pops a primer. =)

Also have a new scope to try. Purchased a Athlon Argos. Not as nice as my Midas but should be better then my 15YO Bushnell that was on it.

Have a wonderful Thanksgiving guys!

[CFJunkie]

TommyD,

Seating your bullets out beyond SAAMI recommended O.A.L. is primarily a means of achieving a desired jump to the rifling on your specific barrel.
If you have measured your chamber and know where the rifling is in your specific barrel for the 77 SMK bullet, you should already know the specific O.A.L. to that will achieve the desired jump you are aiming for that bullet.
I assume that you did that and aren't just using someone else's data.
I also assume that you also know that the desired O.A.L. will be different for each bullet type and brand, since the position of ogive changes with bullet weight and design parameters.

As both charlie b and I have noted, that desired O.A.L. will change as the rifling erodes with use.
My rifle actually changed 0.036 with 3,000 rounds of wear, so my seating depths to maintain the jump I desired have grown from what they were when the barrel was new.

Just so you know, every 0.002 you increase your O.A.L. reduces your velocity by 1 about fps with a .223 or 5.56x45 cartridge.
It also lowers the pressure as well by a smidgen. That little bit of change won't make enough difference to reduce the impact of loads near Pmax, but sometime a bigger change may help. QuickLOAD will help you figure that out.
But I would suspect that you already know that if you are using QuickLOAD and are observent to the impacts of changes in seating depth and trim length.

[TommyD11730]

Yes Sir, I used the Lock and load to find the ogive. That being said when I accidentally created a load with more jump 2.23 vs 2.29 I thought I would also try the TMKS "short" as well. Mostly to see if increased jump did help along with the increased velocity of the shorter round.
Thanks for your reply, and as always your information.

[TommyD11730]

What's the old saying about a bad day at the range vs a good day at home. :)
The weather here was truly a gift, very warm and dead calm.
I fought my rifle pretty much all day. More so the scope. Now I know the Athlon Argos is hardly a high end scope. However I had a lot of trouble keeping a clear target picture at 200 yards. Even turning the mag down to 24 or so power it just looked blurry to me.
Anyway enough about that. The 77 TMKS I loaded were ok... Just ok at 200. The COAL of 2.285 is well short of the 2.385 I fired the week before. So while the new rounds had much less drop (23.5 vs 22) the groupings were less tight.
So, I'll go back to my original COAL and keep the charge at 23.5 for next week.
My 69SMKS did ok, considering the scope issues.
Hope everyone enjoyed their Thanksgiving!

[hamiltonkiler]

What's the old saying about a bad day at the range vs a good day at home. :)
The weather here was truly a gift, very warm and dead calm.
I fought my rifle pretty much all day. More so the scope. Now I know the Athlon Argos is hardly a high end scope. However I had a lot of trouble keeping a clear target picture at 200 yards. Even turning the mag down to 24 or so power it just looked blurry to me.
Anyway enough about that. The 77 TMKS I loaded were ok... Just ok at 200. The COAL of 2.285 is well short of the 2.385 I fired the week before. So while the new rounds had much less drop (23.5 vs 22) the groupings were less tight.
So, I'll go back to my original COAL and keep the charge at 23.5 for next week.
My 69SMKS did ok, considering the scope issues.
Hope everyone enjoyed their Thanksgiving!

Sorry maybe I am miss reading? At 200yds your bullet is dropping out 22” from zero?


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[TommyD11730]

That's grains of powder.
From 100 to 200 it's about 5 clicks of moa to rezero elevation at 23.5g of powder. At 22g it's a good 3 inches lower.

[hamiltonkiler]

Hah I was like what In the world.


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[charlie b]

And I thought it was the markings on the scope, 23.5 vs 22 is 1.5MOA (unless you have a mrad scope).

[TommyD11730]

A cold and windy day at the Range this weekend. Had a easier time behind the Athlon scope. Found I'm a better shooter at lower mag. Aim small miss small? Parallax better adjusted at lower mag? Not really sure.
Anyways I'm very pleased with these 77 TMKS. So much so I ordered 500 of them today. They are every bit as accurate as my favorite 69 SMKs. When moving from 100 to 200 yards they only drop 1 more click (.²⁵ moa) vs my 69s. Just to recap my 77s are 2.385 coal @ 23.5 grains of Varget.