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1 in 10 twist on a .243 barrel ?


malkiserow
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My last 243 would shoot 55's into 1/2" 58's the same. 75's were better as were 80's and 87's 55's & 80's were Sierra the others Vmax.

it would put PPU 100's into an inch all at 100 yds. it wouldn't shoot 105's.

 

My new CZ is about the same with PPU 100's and loves the 87 Vmax best group is under 0.4" My mate uses the same load in his parker hale one hole groups the norm.

 

He also uses PPU 90's which give about 3/4" groups.

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It depends! Twist rate is no guarantee and its shape (length) not weight that will or wont dictate what can be stabilised, speed also has a fair bit to do with it.

 

As a guide

I have yet to find a 1-10 that wont shoot 55 grn to 85 grn bullets of various shapes, there will always be favourites among that group as regards type and brand that most suit you barrel though. 85-95 grn bullet choice is just a tad more techy on brand to brand barrel to barrel. I should also consider the other load details 95 grn SST wouldn't shoot fantastically in one of mine till I really booted them out the end yet I had a mate with the same gun who had these functioning very well at lower pressures- that just the Heinz 57 of it, mine wouldn't even with his load.

100 grn bullets are often said to not stabilise well, however I have another take on this one. Bullets built with terminal performance in mind often utilise methods of construction such as separate front and rear cores, this is contrary in principle to a target or varmint type bullet built for accuracy! If it matters that your gun shoots just outside MOA at 100 yards instead of 1/2 that or less you are worrying about nothing, these bullets are meant to crash deep into outsize for calibre game, so ask yourself what is relivent to the use intended. Choose a flat base over a boat-tail bullet (pro-hunter over Game-king in sierra are basically the same but the pro-hunter is the flat base) it (the prohunter, will shoot better in 99 out of 100 1-10 .243) My current .243 win has achieved quite a few three shot from cold screamers (calibre group) with 100 these and vhit 160, five shots is beyond it unfortunately with the sporter barrel :sad1:

 

105 hunting bullets are not honestly needed, have a look at what 5 grns of lead looks like- if they perform for you fine they do in some 1-10's but they cannot be expected to add anything. VLD target bullets over 100 grn certainly need a faster twist, expect to loose something at the bottom end though with those fast frangible and often very useful 55's and 58's. which likely or not wont shoot from a 1-8.

 

The .243 win has been at the top seller list of hunting rifles for many years, others have attempted the hunting quarter bore but non have taken its slot, I put forwards the fact that its the 1-10 and its extreme versatility with 55 -100 grn bullets that has sealed this slot. :yes:

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100g seems to be the interesting point, some 1-10 can handle with some ammo whilst others are not so keen, if you are looking for more than 100g .243 shooting, then I have to suggest 1-10 is not the way.

 

Mine loves the 90g PRVI SP which it lives on (sub 1" all day) , but not so keen on the 100g PRVI. An assortment of Home brews tend to clover leaf in mine. :yes::good:

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I tried various 100 grain factory rounds but could not get any to group well enough. I then tried Geko 105 gr and they were the DB's and were not that expensive, but not easy to get a hold of on a regular basis. I now reload Hornady 100 gr BTSP's bullets and evntually settled on 42.3 gr of IMR4831, Fed 210 LR primer and they group under 1" every time. This is well in for my stalking and I am happy with it.

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Given that a twist rate of 1 in 9 or 1 in 8 could reasonably be expected to better stabilise a heavier bullet, given similar velocities, why is 1 in 10 standard?

Mainly because it gives a good compromise between light prairie dog etc to heavier bullet deer rifle. Remington came out with a similar round which iirc was a slower twist and not as versatile as the Winchester back when they were selling to a one rifle public.

Given that you can get a foxing load good for long ranges and Deer legal heavier loads while change. Tighter twist barrels tend to be found more often on the range for the long range VLD bullets etc.

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Given that a twist rate of 1 in 9 or 1 in 8 could reasonably be expected to better stabilise a heavier bullet, given similar velocities, why is 1 in 10 standard?

 

In many ways the 6mm Remington was the better of the two but they put it out as more a deer rifle with a faster twist to stabilise heavier bullets. Lets be fair it then had to plat second fiddle to all the .25's and 6.5's etc. THIS IS BASICALLY WHY once you go bigger might as well go the whole hog!

The 1-10 twist .243 win can shoot as flat as .22-250 with 55's and yet can handle 75-85 great for smaller deer / large vermin and still remain an effective large deer rifle with light recoil and 95-100 grn bullets. Heck perhaps that's why its been one of the most popular choices for many a year. Its going to be hard to displace it, having looked at the other options myself you gain little but more expensive harder to obtain ammo and components while remaining in the 6mm

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bullet weight is not all the info you need

some 100gr+ loads will work if you find the velocity sweet spot

 

similarly I am shooting 60gr .224 through a 1:14 .222 barrel

in theory and on paper it shouldn't work

 

in practice the groups shrank from 1 to 2" down to 3/4" then back up to 4" as the speed increased from a starting load

As soon as I pushed them faster than an estimated 2900-3000fps they opened up like a shotgun!

 

with seating depth tweaks I put it under 1/2"

 

 

http://www.thestalkingdirectory.co.uk/showthread.php/60376-heavy-for-calibre-bullets-in-222?highlight=60gr+.222+load

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