factory vs. handload ballistics questions

[Scibaer]

i wonder if there is any reason to think that i would get similar point of aim if i handloaded some rounds to match the factory specs ?
 i have 170gr. RN factory 30-30 Federals, claim to be 2150 fps.
now if i handload some rounds to match the weight and stated velocity, regardless of powder used, could i expect to be close when it comes to point of aim, related to zero at 100 yards ?
 i have about 30 factory rounds. if i zero my marlin 336 in with them and make up some handloads that are the same weight bullet , running the same velocity, will i be close to the factory POI ?
or is this not going to work ?
glenn

[Brithunter]

Well it should work, the thing is you need to check that the bullet you use will have a similar profile and bearing surface to the one in the factory load, now I developed a load to shoot to a set of express sights and duplicate the old Kynoch load that still shot to the sights. Of course commercial ammunition is not available in 6.5x53R which is what I was working with but using the Hornady 160 Grain RN and Reloader 19 powder and in re-formed 303 RP brass. It shoots to the express sights at both 100 and 200 yards  well as best as I am able to tell.

[R.W.Dale]

i have 170gr. RN factory 30-30 Federals, claim to be 2150 fps.

One thing you cannot do is assume the manufacturers claimed velocity has any founding in reality. You first have to chronograph some factory ammo of find out what the MV is from YOUR rifle.

An example is Ive chronographed 170grn Remington 30-30 ammo as slow as 1800 fps from a 20" barreled savage 340

i have about 30 factory rounds. if i zero my marlin 336 in with them and make up some handloads that are the same weight bullet , running the same velocity, will i be close to the factory POI ?

Not necessarily,  A tricky element called barrel harmonics come into play. Changes in even one variable from factory ammo particularly burn rate of the propellant can greatly change POI even at similar velocities.

or is this not going to work ?

Take my advice to heart, trust me on this NEVER NEVER EVER hunt with a load you're not sighted in for

[jhalcott]

+1 what Krochus said!!! Every gun seems to be a law unto itself. Verify your loads.

[skb2706]

i wonder if there is any reason to think that i would get similar point of aim if i handloaded some rounds to match the factory specs ?
 i have 170gr. RN factory 30-30 Federals, claim to be 2150 fps.
now if i handload some rounds to match the weight and stated velocity, regardless of powder used, could i expect to be close when it comes to point of aim, related to zero at 100 yards ?
 i have about 30 factory rounds. if i zero my marlin 336 in with them and make up some handloads that are the same weight bullet , running the same velocity, will i be close to the factory POI ?
or is this not going to work ?
glenn

Given the range that you will be using a 30-30 it will be very close. so much so that you will make errors in aiming iron sights greater than the difference in the two different rounds.

[iiranger]

Frankly, this is where you start. You assume it should be close, but TEST! As said, guns are different and if it doesn't work, try another load... With a .30/30 your odds are good that it will be close. .204 Ruger and you would be one lucky Jose! luck.

[Siskiyou]

The top two are Remington 150-grain C-L factory loads purchased at Wal Mart on sale.  Bottom two are my handloads using IMR4320 and 150-grain Hornady Round Nose.  Does this prove that my handloads are inferior to factory ammunition?  Rife 30-30 Marlin, Model 336, with Burris 2x7x35MM scope set at 7X.

[Badnews Bob]

Nah just that you missed that little orange dot every time.

[Siskiyou]

Aging eyes!

[Scibaer]

ok, i have some things to think through and ultimately test out.  it sounds like i could come close, if do things right when i load up the rounds.
 finding the true velocity of the rounds is going to be an important factor.

the one question i was wondering about , but did not ask was does the bullet shape effect accuracy ? i know it effects performance when in contact with an animal, but does it effect accuracy.. i mean other then the bearing surface, does the meplat matter.
if one bullet has a slightly shallow radius curve then the other, or if the tip has  a sharper point, wil that effect accuracy ? or is it only bearing surface that matters then?

[Graybeard]

If you've done any serious load development work using incremental charges of powder with same bullet and with multiple bullets especially the one thing that should have become clear to you is that you just can never tell where that bullet will go until you shoot it and find out.

I've done this where I'd use three or four bullets of same weight and different manufacturers or construction from same maker (such as Nosler BT and PT). I'd start at the beginning load and work up to max in half or one grain increments and take them all to the range and begin shooting until they wre all gone then take the targets back and compare group sizes and group placement on the target sheets.

I've found that often a single grain of powder with all else equal can shift bullet impact by inches and when you change bullets of same weight for a different bullet with all else being equal I've seen POI shift by several inches and they might be high or low left or right of POI with other same weight bullets of different make.

So can you assume your hand loads will hit to same point as factory ammo? In a nutshell Nope you sure cannot.

[Brithunter]

Godd question and one which I doubt anyone really knows the answer. Internal ballistics does not appear to be an exact science as no one knows or seems to be able to proove why some bullets are more accurate in a particular rifle than the next bullet. External ballistics seems more sorted at least to me  however the way the bullet exits the barrel and the spin rate will effect how it's presented to the air resistance. Too much spin............ i.e overstabilised and the nose will not follow the path of the bullet and as it slows down will likely to cause wobble but that's at extreme range.

I guess I was lucky as I got mine to regulate just by trial and error as I didn't have access to a chrongraph. You will find things which are quoted as gospel about bullets in certain calibres and chamberigns are not quite as they seem. I have always read that the 6.5x54MS does not like light bullets yet have found that I get good accuracy from Speer 120 grain Hot core (flat based bullets). One day when i get ti re-stocked I am hoping to try the lighter 6.5mm bullets through it. Oh and according to the experts it should not shoot with any accuracy at all as the grooves are oversize as they measure 0.268" instead of 0.264" even though the bore size is 0.256" and both 6.5mm Steyr's I have have these dimensions  .

So go for it  .............. it's the only way your going to find out with your rifle one way or the other. Just let us know how it turns out  ........... PLEASE 

[Scibaer]

well , i am new to reloading. thats why i ask so many questions that are well, noobie questions.
but i am taking handloading serious and endeavor to work up safe, accurate, repeatable loads.
i do have many questions related to serious load development, and this is one of them.
 i have a 1949 Marlin, model 336 RC. it shoots the Federal 170 gr. RN real well. so i am looking to use that as a starting point for my own load development.
 i do know that i cannot replicate the factory powder. but i have choosen to start with IMR 3031, 26.5 grs. in 1/2 grain increments to work up a load, trying to match or better the accuracy of the factory Federal load.
as a side note, it was one box that shot so well from my rifle.

also i can assume then by Bill's comment, that i will get different POI from rounds that have a muzzle velocity of different speeds.. but by how much ?
i'm sure that 500 fps is a major POI change, but what about 50 fps ? at 100 yards will a major change be measurable ?
i know that the only way to know for sure it too shoot , record and find out, but what have you more experienced guys seen ? at what point does the muzzle velocity effect the 100 yard POI ?

[R.W.Dale]

Ou can get greatly differing points of impact with NO change in velocity.


I'm gonna grossly oversimplify this


When you fire a rifle the shock from the exploding powder and the bullet slamming into the rifling sets up a high frequency wave that travels down the length of the barrel and back causing the muzzle to move about slightly. Change any variable that gets the bullet leaving the muzzle at a diffrent part of the wave and the poi can change sometimes dramaticly.

The only way you can possibly know is to shoot the thing

[Scibaer]

well i've been to the range. there is really no consistant accuracy between factory loads and handloaded ammo.
 with my best efforts, there are so many variables that change the POI, that at  100 yards 6 or 8 inch changes in POI are seen.
 my best method, was to take apart a few factory rounds, and reuse everything except the powder.  i replaced the unknown powder for a known brand, and matched the muzzle velocity of the factory round. at 50 yards a six inch group was the best i could do.
i can only assume that even how a powder burns, makes a difference in accuracy.
i had about 40 rounds and about half of them were Win. brass and the rest were FC. i weighted the brass empty and when the round was complete. they were consistant within .4 grains. at the range the FC cased rounds were 1/2 inch closer as a group then the Win. brass.
so, even the brass itself can , or atleast in my test, make the POI accuracy different.

my testing was done at an indoor range, with a solid rest. with enough time between shots to keep the barrel cool. all the rounds i used were sized the same, using cci benchrest primers, and the powder was carefully metered and all components were as close as possible, i even weighed the bullets and made sure they were as close in grain weight as possible. the rifle itself, zeroed at 100 yards, with my handloads shoots 1 1/2 inch groups.
 trying to match factory rounds, i get 6 inch groups. a few shots were over 12 inches from the X.. i dunno why or how.
i think this is a closed issue for me, lol