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Is there a such thing as a preferred bullet weight for a specific barrel or is simply a matter of having enough twist to stabilize that length of projectile? When someone refers to their rifle not liking a particular weight is this a euphemism for not having enough twist for that length of projectile?
You're not a bot are you bro?
Greetings Magnetite,
There are many many things that have an effect on how well a particular rifle or barrel shoots a particular projectile. These can include but are not limited to barrel twist, throat length, how abrupt the leade is, powder charge, primer and for all I know the phase of the moon and how you hold your mouth when you pull the trigger. To this is added how well the rifleman can hold the rifle, how good the scope and their eyesight is. Certain projectile weights and styles can provide better performance in a particular rifle or calibre but even this can change over time. Many moons ago when there were no such things as laser range finders and dial up scopes (no cell phones or even pocket calculators for that matter) we trod the trails in the Kawekas with 150 grain projectile loads in our .303 or .308 rifles because the extra velocity gave us a longer point blank range, or thought it did. We couldn't see anything in our 2.5 and 4 power scopes all that far away so trajectory was largely ignored. These days with range finders, dial up scopes and hold over reticles that .308 is more likely to be loaded with 165 grain or more projectile cartridges and the scopes are 4.5 to 14 power or more. Old fudds using the 150 grains are considered backward.
To summarise, yes there are preferred projectile weights but they change over time and everybody has to find their own. Happy hunting for yours.
Regards Grandpamac.
Attachment 148329Quote:
Originally Posted by stevodog
Using the following projectiles as an example for a 6.5mm:
129gr and 140gr Interlock, and 129gr SST and 140gr SST.
Lets say the rifle prefers the 140gr Interlock over the 129gr. I can make two assumptions:
A: Because the rifle prefers the 140gr Interlock it will prefer the 140gr SST over the 129gr SST.
B: There is no correlation in preferred weight with different bullet types.
If A is correct you can test different weights of the same type of projectile and find the rifle's preference.
If B is correct, either test each bullet or compare the desired projectiles in a calculator and then test the top option.
I think I came across a table of recommended bullet weights for various twist rates, I'll see if I can find it again.
Couple of websites...
https://thebloke.co.nz/matching-twis...ght-in-rifles/
https://www.everydaymarksman.co/equi...ng-twist-rate/
Anyone using SST's on big game should themselves be shot. But that aside look up a twist rate calculator. I have used the old Greenhills formula from Hatchers Notebook - a Military formula for shells adapted to small arms. With it, the range of projectile weights that will be stabilised by a given twist rate in a certain bore size can be calculated. It is a ratio, the larger the bore the slower the twist, the longer the bullet the more twistQuote:
Originally Posted by Magnetite
Greetings All,
I think that there is one thing that we have glossed over. Our first step should be to decide what we are trying to achieve. If our load is primarily for long range shooting or is it for sneaking around in the bush and semi open country. This should narrow the range of projectiles we would consider. Next what are the capabilities of the rifle. Is the twist fast enough to stabilize the projectile, is the mag long enough to seat the projectile with the ogive outside the neck. We may find that the rifle is not up to the job. There are two options here change our aims or the rifle. Now and only now is the time to start putting some test loads together.
For bush hobbit's none of the above matters much but for those with longer range intentions we are much better of starting with our aims rather than tables of mythical ideal projectiles cooked up by someone on the other side of the world decades ago.
Regards Grandpamac.
