110 GR. Vs. 112 GR. .308 Bullet Trying To Understand a Proper Powder Load

ki11ercane

ki11ercane

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I was looking at the Hodgdon website tonight to figure out a load for a 112 grain .308 bullet and I could not find it. However, I found this:

110 GR. BAR XFB Bullet
Hodgdon BL-C(2) Powder
.308" Caliber
2.800" C.O.L.
48.0 GR. Powder Load
3061 FPS Velocity
42,400 CUP Pressure

The bullet I want to load is 112 GR and is the same length as a 180 grain bullet.

So to the experts here:

Is it as simple as basic algebra to up the power load to match the bullet weight to keep it at 3061 FPS? It's a 1.786% additional weight to the bullet, so the math dictates upping the powder load 48.86 (48.9) grains to keep the same velocity. (again using a simple algebraic equation) Or does this increase (however slight) have a negative/dangerous affect on the case pressure vs. the bullet? The same table shows the maximum powder load for the 110 grain bullet to be 52 GR, so my change in powder weight is still below the maximum load limit for a "110 grain bullet."

I just want to make sure my logic is sound at least on the starting load line. I'd rather stay at 48 GR. for my loads and I don't care about a velocity drop of 54 FPS. But is it only a drop of 54 FPS? Again, using the same math, will I see only a 1.786% drop in velocity (3007 fps) or is there another mathematical equation at work that drops the velocity say exponentially? (ie. will this bullet that's 1.786% heavier using the 110 grain powder load out see a significant velocity drop vs. using math to figure it out?

Sorry if my question sounds convoluted, but it's the only way I know to explain it. (ie. using a math theory)

Any help would be appreciated.

Thanks!
 
The extra player in the heap is called a gremlin.
There is no way you can figure mathmatically, like you are doing, down to such close tolerances.
That kind of work is called trial and error.
Actually, convaluted isn't a bad call!
 
Not sure about all the bullets mentioned here but, your algebraic equations don't take into account the diff. length of bearing surfaces and how that affects pressure and velocity of the diff. bullet designs. I'd find data for your exact bullet from a manual or here on the confuser here and go from there. I wouldn't put so much concern on velocities as alot of rounds show sd's higher then the 54 fps mentioned.
 
firemachine69 said:
Talk about overthinking this.

48.5 grains, and have-at 'er!
Click to expand...

I am about one month and 100 reloads into reloading. I am on the learning curve. I've tried to research the ammo already on Google. Not much to turn up. I will gladly take over-thinking vs. having a right handed rifle (which 85% of all commercial and 95% of all milsurp rifles are) in the hands of a lefty blow up in my face. I am loading these for my M14 for now.

The projectiles are Spanish 7.62 CETME CSP-3 in 112 grain weight with a lead and plastic core. It's an underpowered NATO round. Cheaper than lead cast. About 50% cheaper than FMJBT. Great for target shooting. You can reload with these for the initial cost of under 58c/round, then 38c/round until the cartridge is no longer usable.

If 1/2 a grain is a non-issue, I'll stick to the load data for 110 grain. (48 grains) I have read further that some people used data from 300 Savage (39.5 to 43 GR of BL(C)2 ) or .30-40 Krag (no powder load data for the powder I am using) for these projectiles.

I am simply trying to pull from Experience Pool here.
 
Is it as simple as basic algebra to up the power load to match the bullet weight
Click to expand...

You guys all fail. The heavier the bullet, the lower the powder charge.

ki11ercane, if you start at the suggested starting load, 2grs of bullet weight means nothing. IF you actually have a reloading manual and are not just gleaning data off the net, I suggest you read it.
 
joe-nwt said:
You guys all fail. The heavier the bullet, the lower the powder charge.

ki11ercane, if you start at the suggested starting load, 2grs of bullet weight means nothing. IF you actually have a reloading manual and are not just gleaning data off the net, I suggest you read it.
Click to expand...

Thanks to enfield p for the PM help. My question has been answered now.
 
You will get bette results with a faster powder. That ball powder at low pressure will be very dirty. For that bullet I would use something like 4198 to make a good plinker.

The approach I use with a new bullet situation is to find a somewhat similar weight bullet, a suitable powder listing that i already have on hand and start at the START load. I load 5 of each, going up in .5 gr increments, and shoot groups. I am prepared to stop when I get prssure signs and bring some ammo home, to pull apart.

Hopefully one of the groups looked good, and I then have a good plinking load.

I made ammo similar to what you decribe, about 30 years ago, using BLC2. Each round was a CLICK-BANG. About a half second delay. Good proactice ammo for checking for flinches.

Problem was solved by changing to a magnum primer. A fast stick powder would be the best fix - like 4198.
 
Ganderite said:
You will get bette results with a faster powder. That ball powder at low pressure will be very dirty. For that bullet I would use something like 4198 to make a good plinker.

The approach I use with a new bullet situation is to find a somewhat similar weight bullet, a suitable powder listing that i already have on hand and start at the START load. I load 5 of each, going up in .5 gr increments, and shoot groups. I am prepared to stop when I get prssure signs and bring some ammo home, to pull apart.

Hopefully one of the groups looked good, and I then have a good plinking load.

I made ammo similar to what you decribe, about 30 years ago, using BLC2. Each round was a CLICK-BANG. About a half second delay. Good proactice ammo for checking for flinches.

Problem was solved by changing to a magnum primer. A fast stick powder would be the best fix - like 4198.
Click to expand...

EXTREMELY HELPFUL! Thank you! This augments the information I already have on hand. 4198 was what I was going to use on my .308 loads and keep the BL(C)2 for my .223's.

Again, thank you!
 
Ganderite said:
You will get bette results with a faster powder. That ball powder at low pressure will be very dirty. For that bullet I would use something like 4198 to make a good plinker.

The approach I use with a new bullet situation is to find a somewhat similar weight bullet, a suitable powder listing that i already have on hand and start at the START load. I load 5 of each, going up in .5 gr increments, and shoot groups. I am prepared to stop when I get prssure signs and bring some ammo home, to pull apart.

Hopefully one of the groups looked good, and I then have a good plinking load.

I made ammo similar to what you decribe, about 30 years ago, using BLC2. Each round was a CLICK-BANG. About a half second delay. Good practice ammo for checking for flinches.

Problem was solved by changing to a magnum primer. A fast stick powder would be the best fix - like 4198.
Click to expand...

Well here is what I decided on.

One, I wasn't sure you meant H4198, or IMR4198. Cabela's only had IMR 4198. On the burn speed table, IMR4198 sits at 57 and H4198 sits at 58. They are VERY CLOSE. So the IMR burns faster. It's also a stick powder as you indicated. Instead of using the magnum primers, I will stick with large rifle primers because of the slightly faster burn rate. So to summarize:

Powder - IMR4198 (stick powder)
Primer - Large Rifle
Cartridge - Military IMI
Bullet - CETME 112gr.
Powder load - 35gr. (110gr out of the Hodgdon data sheets states 37gr for minimum load. I am backing off 2gr. for the difference in bullet weight, burn speed, and cartridge thickness)

I am going to go up increments of .5gr and stop at 37gr and check for pressure. If there is no pressure issues, I'll head up two more .5gr increments. 40gr is the maximum powder load, so I will stay under by 2gr. based on the powder, cartridge, and bullet weight.

I'll be shooting it in an M14.

After talking to several people, receiving PM's, checking online, reading over four different loading manuals, pouring over a pile of articles, this is what I have come up with.

I'll post an update once I load and shoot it.
 
Ki11cane, some manuals don't make any distinction between bullets that are 5 grains in weight. If you are within acceptable limits for 110gr bullets, you should be ok. My only concern would be the length of the bearing surface of the bullet and the hardness of the lead in the base. I doubt it will have little if any effect though. H4831 is right. You're splitting hairs on a gnats bottom. Not all powders are created equal and vary actual burn rates from lot to lot. Ganderite is correct, that will be a dirty load with ball powders. The cartridges they were pulled from had a flake type powder. Usually a fairly fast and clean burning type of powder that we don't see much of any more other than in pistol and shotgun powders.

Flake type powders were the original smokeless powders used by the French and Germans. Nitrocellulose based.

I hope chemist sees his way into parting with some of that powder.
 
bearhunter said:
Ki11cane, some manuals don't make any distinction between bullets that are 5 grains in weight. If you are within acceptable limits for 110gr bullets, you should be ok. My only concern would be the length of the bearing surface of the bullet and the hardness of the lead in the base. I doubt it will have little if any effect though. H4831 is right. You're splitting hairs on a gnats bottom. Not all powders are created equal and vary actual burn rates from lot to lot. Ganderite is correct, that will be a dirty load with ball powders. The cartridges they were pulled from had a flake type powder. Usually a fairly fast and clean burning type of powder that we don't see much of any more other than in pistol and shotgun powders.

Flake type powders were the original smokeless powders used by the French and Germans. Nitrocellulose based.

I hope chemist sees his way into parting with some of that powder.
Click to expand...

Cabela's had eight pounds on Monday. It wasn't even in their database. By today, they had five. I bought three. I want to verify this load before going balls out on 1000 rounds. (5.3lbs) If I don't like it, at least it will be easier to sell 2lbs vs. 5lbs. I picked up some BL(C)2 for the other two pounds of IMR 4198 I didn't buy (which I am using for .223 right now) but what I am going to do with that is change to Magnum primers to make the burn hotter and maybe that will make less of a dirty load. The only thing is it's 48 grains for BL(C)2 so that's 43 less cartridges per pound or 1.5 lbs more powder per 1000.
 
BLC2 and IMR4198 are pretty close on the chart as far as burn rate goes. I think you've answered your own question as well. You're going to use the cartridges in a gas operated semi auto rifle. The powders you list may not be ideal but they will be more than satisfactory and consistant. Just hope your surplus bullets are as good as your powder choices.
I ordered a couple of thousand of those bullets as well. I would prefer to load them with their original powder if possible.
 
19 posts on how to find a load for a bullet 2 grs heavier than listed? Lots of over analysis that in the end means nothing. Use the load for the 2 gr lighter bullet, or for a bullet a few grs heavier.
 
But Andy, you have to remember that many of those 19 posts were by long time reloaders. And everybody knows you can't go by what the old timers say. They were haywire, knew nothing about reloading or shooting and it is just a miracle that they are still alive!
Would you believe many of the old timers don't even go by everything that is written in the modern loading books?
We all know we have to follow every word in all the loading books and we must never experiment, or try something different, because that would just lead to a KABOOM/blow our fingers/hands/feet off, or at the very least put the cat into orbit.
 
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