Bullet length vs. bullet mass in reloading recipes

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RatFink

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Hey guys,

Another inexperienced question for the experienced out there:

Looking at the Barnes catalogue, I see that the 150gr TSX Flat Nose (meant for 30-30) is give or take the same length as a 130gr TSX/TTSX in .308, so theoretically speaking, would you use the 150gr TSX/TTSX data to load the TSX-FN in a .308 or could you step down to the 130gr TSX/TTSX data and eek more velocity out?

When the bullets are the same exterior dimensions aka: contact patch in the barrel, what is the deciding factor for gunpowder load given that you would have more available case volume with the shorter projectile? I see the data is about 2 grains apart, which could make a huge difference in terms of safety, as you step up from the minimum load starting point.
 
Go by bullet weight. If you are shooing the 130gr, use the 130gr load data, in the caliber you are shooting.

Heavier bullets generally have a longer bearing surface, which only reinforces using the correct data by weight.
 
150 grain data is 150 grain data.

So if your book lists 150 grain data for 308 you could load a spitzer, round nose of flat nose with that data as long as you start at the bottom and work up.

Using 130 grain data may not be safe as lighter bullets have less mass and usually have less bearing surface so they require less of a push to get them down the barrel.

Your starting charge in a 130 would probably be say 2 grains higher then 150 grain starting charge which may be safe but, by the time you got to max levels using 130 grain data you may be way too hot. Every gun is different though.

As always start low and work your way up watching for signs of trouble.
 
Thanks guys, I understand the basic concept of safety for starting low and with the appropriate powder charge per mass of bullet.

For discussion's sake ONLY though, can someone actually comment on what factors fully affect a bullet's ability to go down a barrel and not blow your gun up?
If I had 2 bullets with the EXACT same physical dimensions in every single way, but one was heavier than the other (they weigh 130gr and 150gr but have the dimensions of the 130gr) does the extra mass of the second bullet actually create a dangerous situation if you were to use a 130gr loading chart (which we have now seen to be about 2gr difference)? Apart from the 150gr bullet needing extra energy to get going since it's heavier (thus generating higher chamber pressures), wouldn't it actually benefit from the greater charge on the other end of the muzzle? Given my inexperience, I would almost hypothesize that having a load like this would almost be like loading a mini magnum since you gain additional case capacity and are pushing a heavier bullet at a comparatively greater velocity (assuming your action is strong enough, etc.)

Again, this is just for discussion's sake. I do not plan to blow my face off.
 
What does Newton's laws of physics say...
Or was Newton's laws of motion?
Whatever. It's the weight of the bullet, not the bearing surface (it plays a part, but not nearly as critical as the weight).
Bullet construction is more of a factor then bearing surface even.
 
RatFink said:
Hey guys,

Another inexperienced question for the experienced out there:

Looking at the Barnes catalogue, I see that the 150gr TSX Flat Nose (meant for 30-30) is give or take the same length as a 130gr TSX/TTSX in .308, so theoretically speaking, would you use the 150gr TSX/TTSX data to load the TSX-FN in a .308 or could you step down to the 130gr TSX/TTSX data and eek more velocity out?

When the bullets are the same exterior dimensions aka: contact patch in the barrel, what is the deciding factor for gunpowder load given that you would have more available case volume with the shorter projectile? I see the data is about 2 grains apart, which could make a huge difference in terms of safety, as you step up from the minimum load starting point.
Click to expand...

I can't really answer your question regarding bullet weight/load data, but I do load the TSX 30-30 FN bullets in my 308win.

42gr of IMR4064 is borderline a compressed load with the bullet seated just off the lands. Accuracy is excellent, and velocity is just under 2600fps in an 18" barrel. It's a low recoiling load.
 
I think you might be approaching this from the wrong direction. You might be thinking of the loading manual as a recipe book. it isn't.

It is a report on the results someone got in THEIR rifle. The assumption is that you will load some ammo using the START load, using the OAL you find appropriate for YOUR rifle (not their OAL). Once you try that Start load, you are in a position to make some more ammo, either hotter or milder, depending on how the Start load worked.

Each gun is different, If you try someone else's pet load (including the load in the book) you might be in trouble. START means Start here and then adjust as required.

I have rifles that take loads hotter than the load in the book. And I have 2 rifles that are maxed out (1 is over max) using the published Start data.
 
1. Following the average load data for the bullet weight and starting at the average suggested start load is the safest method.

2. The 30-30 bullets are designed for lower velocities and have a softer lead core and could disintegrate at .308 velocities.

I loaded Hornady 170 grain 30-30 bullets in my old 1943 Remington 03-A3 30-06 at approximately 2500 fps for deer hunting. The Hornady 170 grain 30-30 bullet is a inter-lock bullet that locks the lead core inside the copper jacket. Meaning the lead core will not be pulled/sucked from the copper jacket and hold together below the cannelure. So check the recommended velocity range of the 30-30 bullet you plan to use.
 
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