JR__

Incidentally though, i believe the sako/tikka,s perform well with factory 100 grainers, especially sako,s own brand.They could be using a very slow powder, which is apparently one of the tricks to get better accuracy from a 100 grain bullet.

Have you pulled the bullet, measured the length, and compared to other 100gr pills? appropriate twist to stabilise depends on length of bullet primarily, not weight..Just so happens the heavier bullets are longer, so generalisations make it easier to compare off the cuff..

JR

Baldie

 

Well done, I wasn't sure about mentioning the 4" group of the BDS myself when i first posted but it has to be taken into consideration

 

If at a 100yds the group is between 2-4" the group at 200yds will therefore be between 4-8" combine this with all the other factors calculated into margin of errors then a miss at 200yds can be common

 

If the grouping achieved at 100yds is not at or below 1" then I would suggest a slightly lighter bullet that groups better as it is shot placement rather than bullet weight or caliber that is the crittical factor in a clean humane cull of any animal

 

Ian

Sometimes forget that some peoples version of 'acceptable groups' is often not quite what I'd accept as accurate. Took me years to convince the good ol' boys back home that the fact you hit a 1 gallon milk jug at 25 yds was probably not the best test, and 'sighting in' was explained as 'well you take your first shot on the deer and see where you miss, then you adjust and keep shooting until you hit it, or run out of ammo.'..Bless 'em..

JR

The reason i posted this question was because my friend shoot deer with his heym 243 using 100gn fed powershock.we recently did a bit 100yd target shooting and it shoots spot on to 100..

He said to me that when out deer shooting deer to 100-150 is no bother but any further out than that is more often a complete miss.

Last thurs we were both out shotting deer and we spotted one around 200-220 out and he asked my for my rifle(6.5x55) to take the shot as he has taken shots at this range before with the heym and had total misses.He took the shot and was bang on for a heart lung.

So what im thinking is that the 243 100gn is losing stability beyond the 100-150yd range...I could be wrong.It might just be him.

If a bullet is unstable at what range would it be noticable..

 

Dwight.

First of all, if you have the barrel handy, you can measure the twist yourself, rather than wait for answers as to what might be the twist. If you have a cleaning rod and fresh brush, run that thru the bore until you just about get to the muzzle. Make a mark at top dead centre on the cleaning rod just where it comes out from the back of the action or rear of your bore guide. Pull the cleaning rod back towards you, making sure it doesn't slip(it needs to freely swivel in the twist) until that mark is again top dead centre. Measure along your cleaning rod from that mark to the back of the action or bore guide, wherever you made your initial. That is your twist rate.

Second. If a bullet is stable at 100-150yds, it's not going to lose stability in the next 100-150 yds. There's probably some other reason.

a 10 twist is the absolute minimum I would use for many of the 100gr projectiles in 6mm/243, and who knows how close to 10 some are using in factory pipes unless you measure it yourself..Better to use faster than 10 if going to the heavy end of the spectrum of 6mm bullets. The reason Remington and the like would use 10 twist is because they are more prone to consider 85-90 ish grain bullets as the heaviest, aren't making rifles for the UK market. I've seen enough difference in group diameters versus twist rates that anyone asking to rebarrel the 6mm for deer would get a recommendation of faster than 10 twist.

JR

Thought I'd cut and paste the post about barrel weights from the old site:

I made a list of some of the weights of barrels I had hanging around the barrelshop. Just for future reference, and they haven't been chopped to finish length, nor chambered or threaded, just rifled blanks in 6 and 6.5mm calibre:

Fluted barrels:

R1(rem varmint) 24.5"--3.6 lb

R2(Rem varlite) 24.5"--3.2 lb

R4(Rem Pss) 26.5"--3.7 lb(flutes were deeper than the R1 by .5mm)

Sako Varmint 22.5"--3.0lb

Unfluted barrels:

R1(Rem Varmint) 26.0"--4.3 lb

R3(Rem sporter) 24.5"--2.8 lb

One barrel with chamber and threads:

Sako Varmint 24.0"--3.1 lb

Some stocks:

B&C PSS 2.5lb

McM mchunter 2.5lb

McM mchunteredge 2.2lb

If anyone has other stocks, rifles, scopes, or other gear they would like to add to the list, please feel free, as can be useful information for future builds..I'll add more when I can.

Cheers

JR