Help with .223 reloads for the Swiss classic green

rdgietz

rdgietz

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Hi All...

I did a search and could not find anything that helped me.. So here it goes.
Just purchased a Swiss Classic Green in 5.56 NATO (with a Bushnell 6500) and thought these things were tack drivers but not having any luck with factory or my reloads. Trying to develop a load for 100 - 300 yrds.

Started with Winchester Brass ... FL resized (Dillon Dies) and cut to 1.760... chamfered in and out.
Federal Match Small Rifle Primers
Varget powder
Sierra 77 gr MK bullets

The OAL was 2.300 inches with a crimp as per the Dillon die suggestion.

I tried 5 shot groups with 8 different loads ranging from
23.7, 23.9, 24.1, 24.3, 24.5, 24.7, 24.9, 25.1 grains

The problem is that i got nothing but 4-5 inch groups at 100 yards with the exceptions of 25.1 grains which gave me a 3 inch group.
No it was not my shooting.. Sand bagged with a 30X scope and a friend shot 5 of this .25 MOA loads from my gun and got the same 3-4 inch group. So what i am looking for is some advice.

Should i cut my cases back from 1.760 inches? say 1.752 (as suggest on the Lapua website)
Should i use a different powder as i cant put anymore Varget in the cases (probably dont want to put any more anyway)?
Should i use a different bullet?
Should i not crimp or crimp more lightly?
Should i use a different OAL?

I just dont know how to proceed from here. Any advice would be appreciated. (and no i dont want to sell the gun, LOL) Thanks in advance for your efforts.

RDG
 
Well, first of all the cases should be trimmed to 1.75. The 1.76 is the maximum recommended length. What twist is the barrel? I have no experience with the 77gn Sierra but if you have a 1-9" barrel, you likely aren't stabalizing them. IMO no crimp is necessary. How much jump is required when seated for a 2.3" OAL?
 
I am not familiar with that rifle but i would think you have a too long of bullet for the twist rate in the rifle. You never mentioned the twist rate but for that you would need a 1 in 8 twist for stability of the bullet. I maybe out to lunch with this but that is where i would look first. What is the rate of twist ?
Lannie
 
Any pressure signs? Hodgdon indicates max 23.7 of Varget for Sierra 77, which is where you started, though you're probably OK, since the .223's small diameter case head is extremely strong (would be nice if you had chrono'd it).

BTW your 2.300" COAL is longer than SAAMI max for magazine length purposes (2.26"), but if it fits in your magazines or if you don't mind single-loading, that's not at all a problem.

If you have a 1-9" twist or quicker, which your rifle almost certainly does, you're not having any problems stabilizing Sierra 77s. If all your mounting screws are tight, the next thing to do is to put the scope itself under suspicion. Either put it on a known-good rifle, or a put a known-good scope on this rifle.

All of the questions you ask about ammo, won't have any effect at this level of accuracy. Those are the sorts of things that turn a 0.75" group into a 0.6" group, perhaps; they won't be the cause of a 3+ inch group.

How are you shooting your rifle? It's been a while since I've held a Sig 550, but I recall that it is fairly "busy" in the forend to barrel contact department. Were you shooting off of a bipod? Or a rest/sandbag in front? Can you shoot in a manner that is somewhat more "free floating" w.r.t. barrel and forend contact? Can you use no front support at all, but shoot it off of the magazine (as a monopod)? If you have a sling or bipod connected, try removing them.

Lastly (you won't want to hear this), it is possible that your rifle really is shooting big groups. My factory Colt AR-15 shoots honest 2.75"-3.0" groups at 100m, and no better (trying differerent known-good target scopes on it, a variety of good bullets Sierra 77s, Hornady 68s, Nosler 55s etc).
 
Some Classic Greens have a 1:10 twist and some have a 1:7 twist. The 1:10 is matched to Swiss GP90 ammo, which has a 63 grain bullet with an all-lead core. 1:7 rifling is required to stabilize the 5.56 NATO tracer bullet.

If your rifle has 1:10 rifling, it won't shoot 77 grain bullets accurately.
 
tjhaile said:
Some Classic Greens have a 1:10 twist and some have a 1:7 twist. The 1:10 is matched to Swiss GP90 ammo, which has a 63 grain bullet with an all-lead core. 1:7 rifling is required to stabilize the 5.56 NATO tracer bullet.

If your rifle has 1:10 rifling, it won't shoot 77 grain bullets accurately.
Click to expand...

"THAT'S what I meant to say :D ".
 
Thanks

Budweiser360 said:
Well, first of all the cases should be trimmed to 1.75. The 1.76 is the maximum recommended length. What twist is the barrel? I have no experience with the 77gn Sierra but if you have a 1-9" barrel, you likely aren't stabalizing them. IMO no crimp is necessary. How much jump is required when seated for a 2.3" OAL?
Click to expand...

Ok... Im a newb when it comes to rifle reloading.. Cases trimmed to 1.75. Check..

The twist on my rifle is 1 in 7. I just measured it and just assumed it was but now that i have measured it i am sure of it..

No crimp.. Check..

Dont know the Jump from a 2.3 " OAL... will have to check that.. Thanks..

RDG
 
Barrel Twist is 1 in 7 inches..

lannie said:
I am not familiar with that rifle but i would think you have a too long of bullet for the twist rate in the rifle. You never mentioned the twist rate but for that you would need a 1 in 8 twist for stability of the bullet. I maybe out to lunch with this but that is where i would look first. What is the rate of twist ?
Lannie
Click to expand...

Thanks again for the question.. I just assumed it was 1 in 7 but now just measured it and it is just that..

RDG
 
rnbra-shooter said:
Any pressure signs? Hodgdon indicates max 23.7 of Varget for Sierra 77, which is where you started, though you're probably OK, since the .223's small diameter case head is extremely strong (would be nice if you had chrono'd it).

BTW your 2.300" COAL is longer than SAAMI max for magazine length purposes (2.26"), but if it fits in your magazines or if you don't mind single-loading, that's not at all a problem.

If you have a 1-9" twist or quicker, which your rifle almost certainly does, you're not having any problems stabilizing Sierra 77s. If all your mounting screws are tight, the next thing to do is to put the scope itself under suspicion. Either put it on a known-good rifle, or a put a known-good scope on this rifle.

All of the questions you ask about ammo, won't have any effect at this level of accuracy. Those are the sorts of things that turn a 0.75" group into a 0.6" group, perhaps; they won't be the cause of a 3+ inch group.

How are you shooting your rifle? It's been a while since I've held a Sig 550, but I recall that it is fairly "busy" in the forend to barrel contact department. Were you shooting off of a bipod? Or a rest/sandbag in front? Can you shoot in a manner that is somewhat more "free floating" w.r.t. barrel and forend contact? Can you use no front support at all, but shoot it off of the magazine (as a monopod)? If you have a sling or bipod connected, try removing them.

Lastly (you won't want to hear this), it is possible that your rifle really is shooting big groups. My factory Colt AR-15 shoots honest 2.75"-3.0" groups at 100m, and no better (trying differerent known-good target scopes on it, a variety of good bullets Sierra 77s, Hornady 68s, Nosler 55s etc).
Click to expand...


To answer your question about Varget and 77 gr HPBT .. i had a few references indicating that you can to up to 25 grains with Varget and this bullet.

For Some reason the bullets still feed very nice at this length. Something about the Swiss Mags...i guess..

I never thought about the scope!!!.. Yes i guess it could be the scope.. I will have to swap it out to another gun that i know shoots well.. and see..

Good suggestion...

I was shooting off the integral bipod at first but then i just sandbagged the fore stock.. but i can try to see if shooting off a monopod will help.. (no Sling)

I am hoping this is not a 3 MOA gun.. but i will try a few things here and see what gives..

Thanks again...
 
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