Ammo 101

[Bhfromme]

I'm fairly new to handguns and am hoping you guys can help me get a better understanding of the different types of ammo that are out there. Let's start the discussion with .38 Special loads. Here are two posts that I just read:

1) Personally, I shoot +P without worry, but I stay away from light bullets (110 or 125 grains). I like to stick with 158 grain bullets, but that may not be all that necessary.

2) If I owned a nice 10-2 in good condition I would only shoot standard velocity, 158 gr. lead bullet loads and 148 gr. target wadcutter loads. I would avoid the hot jacketed +P loads and the 125 gr. flame cutters.


Now I'll probably just stick to run of the mill 158 grain target loads but I'd like you guys to help me understand what all this means.

My first question is related to the bullet weight. Why is a lighter weight bullet harder on a gun? I'm guessing it has to do with the pressure or the velocity but I just don't understand the relationship between weight, velocity and pressure.

My second question is about the different types of bullets. I understand hollow points expand on impact which creates a larger cavity but my knowledge pretty much stops there. What are wadcutters? Semi-wadcutters? When do you want a round point versus a flat point and vice versa? What are flame cutters? What does hot jacketed mean? And then all those rounds with the initials. Holy **** it gets so confusing. Again, I'll probably just shoot standard 158gr target loads in the Model 10 I'm buying but I'm really looking forward to reading your replies. Thanks.

 

[BC38]

Welcome to the revolver addiction.

357 magnum rounds with light bullets and hot powder charges (to get high velocity) are known to be harder on K-frame 357 pistols. It isn't really a consideration with 38 specials, even 38 special +P because they don't have anywhere near the powder charge that the 357 rounds do. The issue with the 357s is that the hot powder pushing a light bullet tends to damage the forcing cone (end of the barrel closest to the cylinder). Do searches using the terms "forcing cone erosion" and "flame cutting" here on the forum and you'll find all the info you could ever want on the topic. Like I said, not much of an issue with 38 specials.

Wad cutter bullets have an essentially flat nose profile. They are basically cylindrical shaped - no pointy end. Semi-wadcutters have a flat faced outer "ring" around a semi-conical shaped center with a large flat nose. Here are a couple of pictures to clarify.

Wadcutter (hollow based variety)

Semi-wadcutter

148 grains is one of the most common wadcutter bullet weights and 158 grains is the most common semi-wadcutter bullet weight.

Hope that helps.

 

[JP@AK]

BC38 made an excellent post and answered some of your question accurately. People hear about the light bullet loads in the .357 Magnum and the stories about its effect on the K frame Combat Magnum (Model 19) and falsely extrapolate that to the .38 Special. That is simply an error borne of a lack of understanding and knowledge. Don't give it another thought.

The bullet illustrations provided above should help you understand the bullet shapes you asked about. I'll add a comment about their purpose. Wadcutters are designed the way they are for target work. The cut a nice clean round hole in the paper target and are therefore favored for target work. Generally speaking they are used in relatively low pressure, low velocity loads. So, they are (theoretically) easier on the gun, but are also easier on the hand, since recoil tends to be less.

Semi-wadcutters provide a similar benefit - clean holes in paper. But they provide a bit better ballistic coefficient because of the tapered shape of the nose. The meplat (front face of the bullet) is smaller than it is on the wadcutter, hence they shed a bit more of the air resistance after they leave the barrel. Semi-wadcutters are frequently used for target work but can also be effective defense rounds. For obvious reasons, they don't open up as well as hollow points, so they are not usually anyone's first choice for defense purposes, but many of them have been used as such over the years.

Finally "hot jacketed" is simply shorthand for cartridges loaded with jacketed bullets over a powder charge that produces higher velocities, which also means higher chamber pressures. Usually when people use this terminology, they are making reference to loads with lighter weight jacketed bullets - that would be the 110 grain and 125 grain bullets in the .38/.357 cartridges. But it would also apply to lighter bullets in the .44, for example.

I hope this helps you understand the issue a little bit better. There is always more to be learned, of course. I've been shooting, handloading and learning about handgun ballistics for about 60 years, and I'm still learning.

So, go out, have fun and stay safe. And keep asking questions and learning. There is lots of collective knowledge and experience available here on this forum. Unfortunately, also some folks who like to talk about stuff they know little about. But, if you stick around, you will learn to tell the difference.

 

[StrawHat]

...then all those rounds with the initials. Holy **** it gets so confusing...

Some of the initials and what they mean.

WC, wadcutter, often for target shooting but some of us older shooters found other uses for them.

HP, hollow point. Some folks like them, others don’t. Me, I don’t have use for them.

JHP, jacketed hollow point. A hollow point bullet wrapped in a copper jacket.

LSWC, lead semiwadcutter. A good all around general purpose bullet. Suitable for most, if not all, uses.

RN, round nose. Usually the first profile offered by the factory in any handgun cartridge. Still available but not favored by many.

FP, flat point. Typically, just what it sounds like.

RNFP, round nose flat point. A round nose bullet that had the “point” flattened.

KSWC, Keith semi wadcutter. A specific type of swc with equal width driving bands, a full diameter front band, square lube grooves and several other details I have forgotten.

I am sure there are others but those came to me quickly.

Hope this helped.

Kevin

 

[s&wchad]

As mentioned, .38 Specials with lighter bullets won’t damage a modern revolver. It’s always wise to read the owners manual and take note of any warning or cautions.

Some of the modern light weight .38 revolvers have a warning on the barrel that reads “... +P jacketed only”. Shooting +P lead bullets won’t harm the gun, but they may seize it up. Jacketed bullets hold the crimp more securely than lead. These light weight revolvers recoil severely and can act as a bullet puller for the unfired cartridges in the cylinder. If the bullets pull far enough, they protrude out the front of they cylinder and render the gun inoperable.

.357 Magnums operate at much higher pressures than .38 Specials and pressure relates to temperature. The issue with light bullets is their length. They’re all the same diameter and typically constructed of similar materials, so the weight is altered by changing the length. 110 grain bullets are very short and leave the case mouth sooner than heavier/longer bullets, often when pressures are near peak. This can cause flame cutting of both the top strap and the face of the cylinder. Some light weight .357 revolvers with titanium cylinders have a warning that states, “No less than 120 grain bullet”. Failure to heed that warning can lead to serious erosion in a short period of time.

I’ll shoot just about any factory ammo out of my .38 Specials. I prefer mid-range lead wadcutters or semi-wadcutters, with the exception of guns with a titanium cylinder. S&W warns not to use anything abrasive on that material and lead build-up is an issue, so I only use jacketed bullets in those guns.

 

[stansdds]

38 Special +P ammo is safe in a Model 10-2, but, just like with any firearm, +P ammo will accelerate wear. Will light weight bullets in 38 Special +P cause flame cutting on the inside of the top strap? Not likely and not likely to cause excessive erosion of the barrel's forcing cone. These issues are related to the operating pressure of the ammo and the burning properties of the powder.

Ammo ............Pressure in PSI
38 Special .......17,000
38 Special +P ..20,000
357 Magnum ...35,000

There is a huge difference between 38 Special +P and 357 Magnum and a huge difference the volume of powder used and the burning rate of the powder.

 

[gwpercle]

There is a important third consideration ...the firearm !
To be specific the age of the gun which goes hand in hand with the steel and heat treating process .

In a model 10 or 10-2 I'm sure it is safe to fire +P loads but it will put more stress than standard loads .... it's not so much a safety issue but a taking it easy on a fine older gun because when it's gone ...no more will ever be made like that .

TC = Truncated Cone ...yes it's confusing , a book , "Cartridges Of The World " available $24.95 amazon) , answers more questions than you could ever imagine and worth every cent !
Gary

 

[Jack Flash]

Since I made Statement 1 quoted by the OP, and given that the comment has been so roundly criticized, I feel like I need to defend it at least a little bit!

First off, read the statement. I flagged it as my personal preference, and if that wasn't enough, added "but that may not be all that necessary." So pretty obvious that this is what I do but no way preaching that others follow suit.

Along that vein, one other comment in the +P thread was from a chap who said he only shoots standard .38 Special loads. I may not agree with him but I won't criticize his preference. I don't know what kind of guns he has, his physical limitations, etc. That's the way he does it, fair enough. No need to take him to task over it.

The sights for the M10s (the ones covered by this sub-forum anyways) were regulated for 158 grain bullets, so there's that consideration.

As well, when I got into shooting handguns, I was influenced by the "heavier bullet / lower velocity" school of thought. Heaven forbid we should launch into that argument here, but it's a consideration, for me at least.

I have indeed shot +P with 110 grain and 125 grain bullets (when that was all I could get) in my M10s with no issues. I no doubt still have at least a couple of half-full boxes of those sitting around here somewhere. Avoiding the stuff may not be all that necessary, but that's my preference.

 

[Bhfromme]

More questions:
I assume SJHP is semi jacketed hollow point ammo. Can someone please tell me when one would want SJHP vs the more traditional JHP?

I also am wondering what standard loads are for .38 Special, .357 Magnum, .44 Special and .44 Magnum.

And when I read guns are sighted at the factory using standard loads, what distance are they sighted for?

 

[stansdds]

More questions:
I assume SJHP is semi jacketed hollow point ammo. Can someone please tell me when one would want SJHP vs the more traditional JHP?

I also am wondering what standard loads are for .38 Special, .357 Magnum, .44 Special and .44 Magnum.

And when I read guns are sighted at the factory using standard loads, what distance are they sighted for?

Back in the day:

SJHP indicates the jacket does not extend to the tip of the bullet, it leaves exposed lead for better expansion. These were almost always revolver bullets, very few semi-auto pistol bullets were semi-jacketed.

JHP indicates the jacket extends all the way to the edge of the hollow cavity, this design is used mostly in semi-auto pistol bullets, but also in some revolver bullets.

These days you see the SJHP nomenclature a lot less often, but the basic design of bullets has changed little. What has changed is jacket design and the alloy of the jacket. Back in the day, the jacket tended to be a relatively thick, copper alloy. With lower velocity cartridges like 38 Special, that jacket would never allow expansion. To get expansion, you either used soft lead hollow point bullets or semi-jacketed hollow point bullets driven at +P velocity. Modern bullet designs, often using lighter bullets, can have the jacket all the way to the hollow cavity and still expand. The Speer 135 grain Gold Dot JHP 38 Special +P is a prime example of a modern bullet.

 

[jcelect]

I just don't understand the relationship between weight, velocity and pressure.

The answer to this part of your question is basic physics! An object at rest, tends to stay at rest. An object in motion tends to stay in motion. A heavier bullet in a charged case requires more pressure(powder) to get it moving than a light bullet. Smokeless powder does not explode all at once, it burns as the bullet is exiting the barrel. This action keeps the pressure behind the bullet from dropping to zero real quick as the bullet moves down the barrel. Velocity is a factor of the amount of pressure behind the bullet, length of the barrel, and weight of the bullet. All of this applies to the bullet in the barrel! After the bullet exits the barrel, everything above, goes south and a whole new set of rules apply! A side note. Again basic physics, the force exerted on an object at rest is equal and opposite, recoil!
I hope his helps you to enjoy your new hobby!
jcelect

 

[BC38]

The answer to this part of your question is basic physics! An object at rest, tends to stay at rest. An object in motion tends to stay in motion. A heavier bullet in a charged case requires more pressure(powder) to get it moving than a light bullet. Smokeless powder does not explode all at once, it burns as the bullet is exiting the barrel. This action keeps the pressure behind the bullet from dropping to zero real quick as the bullet moves down the barrel. Velocity is a factor of the amount of pressure behind the bullet, length of the barrel, and weight of the bullet. All of this applies to the bullet in the barrel! After the bullet exits the barrel, everything above, goes south and a whole new set of rules apply! A side note. Again basic physics, the force exerted on an object at rest is equal and opposite, recoil!
I hope his helps you to enjoy your new hobby!
jcelect

Yes and no.

In terms of physics it is correct to say that it takes more energy to get a heavier bullet moving, and more energy to get a heavier bullet up to the same velocity as a lighter bullet. From that one would think loading a heavier bullet = using a larger powder charge. Oddly enough the exact opposite is true.

When loading heavier bullets the powder charges are actually smaller - because if larger powder charges were used the pressures would be too high and would damage the firearm, specifically because the projectile is harder (and therefore slower) to accelerate from a dead stop. You can think of it like a cork in the barrel. A heavy bullet is like a cork that is really driven into the barrel and stuck hard, vs a light bullet being like a cork just lightly inserted into the barrel. With the same powder charge the pressure will be much higher with the heavier bullet (tighter cork). With a larger powder charge and heavier bullet this issue can be serious enough to over-pressure and damage a gun. A double-charge of powder is a classic example.

So heavier bullets actually use smaller powder charges and as a result the velocity of heavier bullets is lower than what you get with lighter bullets and larger powder charges.

The power of the round is the bullet weight x velocity squared so you can have the same power with a lighter bullet moving at higher speeds as what you get with a heavier bullet moving at lower speeds.

I know that jcelect knows all this, but thought I'd mention it for the benefit of others who may not and who need to understand why heavier bullets use smaller powder charges and light bullets use larger amounts of powder - because it works the opposite of what you would think and is so counter-intuitive.

 

[Bhfromme]

You guys never disappoint. Thanks.

I also am wondering what standard loads are for .38 Special, .357 Magnum, .44 Special and .44 Magnum. Specifically in terms of weight and fps.

And when I read guns are sighted/calibrated at the factory using standard loads, what distance are they sighted for?

 

[BC38]

You guys never disappoint. Thanks.

I also am wondering what standard loads are for .38 Special, .357 Magnum, .44 Special and .44 Magnum. Specifically in terms of weight and fps.

And when I read guns are sighted/calibrated at the factory using standard loads, what distance are they sighted for?

Everyone has their own "pet" loads, and "standard" load depends on which powder you use.

38 special and 357 magnum fixed sighted guns are generally set up for POA & POI to coincide with 148-158 gr bullets - I believe at 25 yards.

44 special and 44 mag fixed sighted guns are generally set up for POA & POI to coincide with 240-250 gr bullets, also at 25 yards if I recall correctly.

The best recommendation is to consult a few reputable published sources of load data to confirm the safety of the powder charge you are using for the bullet you are loading.

 

[Gamecock]

Ammo ............Pressure in PSI
38 Special .......17,000
38 Special +P ..20,000
357 Magnum ...35,000

This is the key.

Shooting +P in a std 38 Special is not going to blow it up. It's not a safety issue. But, over time, using ammo that has a higher pressure than the gun was designed for can "shoot it loose." Stretch the frame, for example.

You can do it. But, if you love your gun, don't.

 

[Gamecock]

One of the great benefits of a revolver over a pistol is you can shoot just about any bullet shape you want. I ♥ wadcutters. No worky in pistols.

 

[jcelect]

Yes and no.

In terms of physics it is correct to say that it takes more energy to get a heavier bullet moving, and more energy to get a heavier bullet up to the same velocity as a lighter bullet. From that one would think loading a heavier bullet = using a larger powder charge. Oddly enough the exact opposite is true.
.

100% CORRECT! Because we have a MAX PRESSURE we must stay below!
jcelect

 

[wv109323]

I will muddy the waters a little more. The .38 spec. cartridge is 120 plus years old. The metals and merallurgy of revolvers of the early years(1900) are not as strong as todays revolvers. So they are more prone to wear and could have untold of rounds through them. The old guns were designed with 15,000 psi in mind. THEN later the +P ammo was made to increase the performance of .38 spec. So putting higher pressure ammo in an old revolver could expodentially cause wear and possible danger.
WC ammo was used almost exclusively as a target round. The WC bullets cut a very clean hole in the paper target. That made scoring hits close to the bullseye target rings easier. For target shooting the emphasis is accuracy not bullet velocity. There is no power factor in bullseye shooting. Bullseye shooting requires 5 shots in 10 seconds. So low recoil provides more time to recover and make a more accurate follow-up shot. Thus WC are low velocity and accurate target ammo.