1:7 or 1:10 twist on a Swiss Arms PE-90/Classic Green/Black Special Rifle (NR)?

Shooster

Shooster

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Hello All,

I am looking for informed information, and personal opinions based on actual trigger time/experience with these two different barrel twist rates (doesn't need to be behind a SAN rifle...could be AR, ACR, XCR, even bolt gun, etc. experience).

I am well aware of the differences these two barrel twist rates are intended for so I don't need to be brought up to speed on the intended purpose of 1:7 or 1:10 barrels.

I am primarily shooting 55 grain and heavier .223/5.56 ammunition - factory and hand loads.

I want performance/accuracy at ranges out to 600m, and perhaps further.

Primary rifle use - gophers, grouse/predator hunting, target/sport shooting, Service Rifle, etc.

If you had to pick one barrel twist rate for the above, which would you go with and why?



Thanks in advance for your help,







Shooster
 
55gr and heavier covers alot of ground. If you don't plan on using bullets heavier than 69gr the 1 in 10" twist will work fine. If you might end up using heavier bullets at the longer distances you will need the faster twist.
 
Shooting Centre said:
55gr and heavier covers alot of ground. If you don't plan on using bullets heavier than 69gr the 1 in 10" twist will work fine. If you might end up using heavier bullets at the longer distances you will need the faster twist.
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Sorry, I should have been more specific. 55-77 grain ammo. 55 grain for plinking at shorter ranges/just having fun, grouse, gophers, that kind of thing. 69-77 grain for the longer range stuff.
 
I sold my 1 in 10 twist to buy a 1 in 7, but never did find one. All I shoot is 62gr and Blackhills Mk262 which is 77gr. That's why I wanted a 1 in 7.
 
You can't overstabilize a bullet so if I had to choose between the two I would pick 1:7.
If you had said you were going to be shooting very light projectiles and reloading for maximum velocity pretty much strictly for varmint hunting at 300yds or less I would suggest the 1:10 since some bullets will come apart after leaving the muzzle if they're spun too fast. I shoot 36gr varmint grenade from my 1:12 twist bolt rifle but my semi auto rifles are 1:7 or 1:8 as I find them to be the most versatile.
My experience with the Swiss Arms classic green flat top I used to own with a 1:7 was not that great, I didn't try anything other than 55gr fmj but the accuracy was not overly impressive compared to other semi auto rifles I own. I'm sure the rifle could have done better with quality ammo but what bothered me and led to me selling it was the 5moa poi shift when I switched from supporting it on the bipod to supporting it on the magazine. A little too much flex for me but other than that it was a beautiful rifle that was built like a tank, I don't think you will ever have to worry about breaking anything.
For serious varminting I would buy a non restricted ACR with a Questar or Herron Arms stainless barrel, an HK SL8, or a nice bolt gun.
Sorry, I know your asking specifically about he SA but for accuracy out to 600yds or more I don't think you'll be happy with the rifle. It's a great rifle but they don't shoot as well as some of the other options we have available to us now and for the price I don't think they generate enough smiles when shooting to justify the price tag.

Just my opinion and I'm sure others will think differently about them but keep in mind that I've actually owned most of the non restricted semi's available to us and my ACR and AR180B-2 remain while the others were all sold off.

Good luck,
If you want to try an ACR before you put your cash on the table and if you're willing to travel north you're welcome to stop by my acreage (45min north of Edm) and try mine. Can also shoot whatever else I have in the safe that catches your eye.
 
Get the 1:7 I have the flat top in 1:7, and use it for service rifle out to 500m. I've had it out to 800m with relative success. 55 grain bullets suck in the wind at 500m. Mine likes 77 grain SMKs, Berger OTMs or Lapuas.
 
For long range precision, a couple of things to consider.

1:10 is good to about 69 gr, so I'd go with the 1:7.

I shot Hungry's PR clinic and match with a 1:10 Pe90, with S&B Match ammo (69 gr rated by S&B to max 1:10), it was ok to 500 m, but at 600 strange things started to happen. My spotter, an international PRS competitor, did not think it was me, or the wind, but something with the rifle, subsequently I found the Pe90's have a wandering zero issue when using the integral bipod, so I think that might have been a factor.
 
john@ said:
For long range precision, a couple of things to consider.

1:10 is good to about 69 gr, so I'd go with the 1:7.

I shot Hungry's PR clinic and match with a 1:10 Pe90, with S&B Match ammo (69 gr rated by S&B to max 1:10), it was ok to 500 m, but at 600 strange things started to happen. My spotter, an international PRS competitor, did not think it was me, or the wind, but something with the rifle, subsequently I found the Pe90's have a wandering zero issue when using the integral bipod, so I think that might have been a factor.
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Yes, the bipod sucks. That's why every single SA owner I know removed it, and shoots off the mag.
 
Tenguns said:
Yes, the bipod sucks. That's why every single SA owner I know removed it, and shoots off the mag.
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+1 for competitions bipod stays home in storage box.
Only time to put bipod back on it is when bush whacking in snow and mud, not for shooting off but for setting down during breaks.

It's an infantry service rifle after all, doing DMR out to 500 is reasonable but treating it as precision rifle is not really the intended usage.
 
I love my Swiss Arms rifles. They're on my never sell list, but nevertheless, you're asking performance from them that they really never were designed for. If you must, as others have said, the 1:7 twist will make you less unhappy at 600M.
 
From my experience with the Swiss Arms they offer excellent accuracy out to and including 500m regardless of twist. Obviously the heavier match bullets offer better ballistics for wind dope, but they are no more inherently accurate than similar quality lower weight bullets, all things being equal.
There are lots of good choices in quality bullets that work with either.
If you are looking for longer distance shooting, you will be better served with a bolt gun and perhaps caliber.
 
Something else to consider when using a pe90 with a scope, you'll want to have a flat top version. Otherwise with the regular one with iron sights you need high rings to clear them, also you will need a scope rail (B&T make one). To get a good cheek weld you'll want to get a high cheek rest. I used a high ar 15 one zip tied on with a cut out piece of thick rubber mat as a spacer (worked really well and way cheaper than the official SIG one,or even the airsoft one).
Also the integral bipod is really tall and the gun sits really high so you will need a large bean bag / stock rest.

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My .02 cents ... I shoot my h&k sl-8. It has a 1/7 twist .... 55 grs..... Total garbage !!! Went with 62 fmj's and heavier and the groups shrank big time .... Even with factory ammo 68 gr hornady and 75 gr .... It's just like a lazer beam ..... 55's I think are good for sweet nothing .... Remember one thing those guns were twins of the military and they shoot 62 grs. Light armour percing 77 grs ap so ya twist has lots to do with bullet weight
 
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