Adelaide wrote:Evening all,
Can anyone tell me how I can establish the twist rate of my Howa 1500 SA .I cannot find any markings on the barrell. What are most accurate projectiles and suggested load data.
Appreciate any help
Take your cleaning rod and a marker and mark a line down its length about 15" or so.
Ideally you want a cleaning rod with a ball-bearing handle so it can rotate freely, but a fixed rod will still work.
Start a patched jag into the bore most of the way until you can align the mark on the rod with a handy rotation datum, like the ejector or sight. Place a piece of insulation tape around the rod in line with a handy length datum that you can access, like the end of the receiver or the muzzle.
Pull the rod back toward you, watching the line as it revolves around the rod. When it is aligned again with its datum, place another piece of tape around the rod at the length datum.
Pull the rod out and measure between the two pieces of tape. It should be close to one of the common twist rates - 8", 10", 12", 14". Do it two or three times to get an average.
The most accurate projectiles will be bullets, but the rifle will really choose for itself which bullet design it prefers the best.
At relatively close ranges you may find a flat-base bullet is most consistent, and a lighter bullet can be launched at higher velocity, spending less time being affected by the wind during its short flight to the target.
At longer ranges you will probably find a long VLD/ELD bullet with a very long nose and a boat-tail base will be distracted less by variations in the wind, which should equate to smaller groups. The boat-tail base is also less prone to being damaged during bullet seating, and the base of the bullet plays a large role in accuracy. But if your throat is not long enough for these very long bullets, you may find that they encroach too far inside the case, eating up valuable combustion volume and limiting the velocity you can launch them at.
Another important part of accuracy is how well the bullet is aligned with the centre of the bore when the cartridge is chambered. This can require seating the bullet out well into the throat, and even pushing it tightly into the rifling before firing it.
A tangent ogive bullet tends to align itself better when it hits the rifling, so it's not generally very fussy about how far it has to "jump".
A secant design is more aerodynamic but is not so good at aligning itself with the bore when it hits the rifling, these can be very fussy about bullet "jump".
A hybrid design has the tangent ogive down to bore diameter (about .216") for the .223, then it has a secant ogive to the point to have less drag. These are less "jump fussy" but have slightly lower ballistic coefficients of drag.
You really have to try them all to determine which works best for you in your rifle.
I hope you don't have the Howa Mini-Action?
You said this was for shooting paper, for precision shooting you will likely be single-loading anyway to avoid any damage to your bullets during feeding.
I would start experimenting with Berger hybrids, depending on your twist rate. Something like the Hybrid Long Range Target 85.5gn if you have an 8"-twist, but this is a very long bullet (.007" longer than the 80gn ELDM) so you need a long throat to get the most out of it, and you will likely have to single-load it as it would be too long to feed through the magazine. But I don't know that there is any supply of Bergers here currently.
Projectile Warehouse do Outer Edge bullets, and have decent stocks of them. I haven't used them myself but they're a machined copper bullet so I would expect pretty good accuracy out of them. They might be worth trying if only because there is decent supply so you shouldn't have trouble getting more of them when you need them.
https://www.projectilewarehouse.com.au/full-packets/?cn=410&rf=cnSierra Matchkings are another good choice to play with, as well as the Hornady ELDM's, and I think supplies of these are still pretty good.
8"-twist will stabilise bullets up to about 1.080" in length (85gn to 90gn), 9"-twist up to about 1.000", 12"-twist up to about .820" (50gn to 70gn).
Load data will primarily come down to which powders you have access to a good supply of.
If I were precision shooting I'd probably start with BM8208 if you can get it, if not then AR2206H or AR2208.