Hi again Pete,

Installment 3: Bullet Tension and Primers

I have tried numerous methods of applying tension to the bullet because I didn’t want the bullet falling out of the case when I handled the cartridges.  I’ve used taper crimps, roll crimps, full length resizing die crimps and even the factory crimp die that one company sells.  I think the company is Lee, but don’t hold me to that.  It’s on one of the shelves in my reloading room somewhere.  At the present time, I neck size all my cases and expand them with an expander plug that is 0.001” smaller that the diameter of my bullet.  This practice has given me the most consistent and most accurate tension.  It is extremely important that the case necks be completely clean to provide consistent bullet pull.  None of my rifles shoot well with a lot of bullet tension.  Little or none seems to work best.

When I first began shooting black powder cartridges in silhouette matches you were in the dark ages if you weren’t using magnum rifle primers.  They worked okay in my 45-70 but when I started working with the 38-50 I discovered that they were too potent for the smaller capacity case.  I started using standard large rifle primers and that eliminated a number of flyers.  One evening, I had some cases that I had pulled the bullets from and dumped the powder from and decided to fire the primers off rather than pulling them.  I went to the cellar and when I fired the first one, I saw a long shaft of flame come out the muzzle of the 34” barrel.  Naturally I wondered what other primers would look like under the same conditions.  I primed a bunch of cases with different primers and headed for the cellar.  All the rifle primers generated a similar shaft of flame at the muzzle but large pistol primers generated a shower of sparks such as you would see if you spark tested a power grinder against metal.  I felt the shower would ignite more powder at the rear of the case than the long shaft.  I’ve been using large pistol primers in all my loads ever since.

If you think about it, ammunition manufacturers had to develop new “hotter” primers when smokeless powder came into prominence because the old “weaker” black powder primers wouldn’t consistently ignite the smokeless powder.  Another consideration is that in a cap lock rifle, the flame from the cap has to pass through a very small hole and turn ninety degrees to light the powder charge behind the projectile.  How powerful or how massive does that flame have to be if it can do that?  I think it takes a lot less fire to ignite the powder column than many of us realize.  I don’t know if the compound used in pistol primers is different from that used in rifle primers or if the amount of compound is different.  I do know that they seem to work better for me.

feather

feather,

    Know what you mean about long posts. I've had to separate a few on here myself. Like you, I can get a little long winded as I try to explain a point that requires more than a yes or no. Sometimes I think I can hear people snoring!

Bullet Alloy

  This is interesting. Your idea of a WW plus 2% Tin alloy is something I don't believe I've seen mentioned in relation to Shilouette, and I know I've never seen it in relation to Schuetzen.

  I'm sure you're right about your conclusions as I've been a firm believer in adjusting the alloy for the MV in order not to exceed the elastic limits of the nose and cause the slumping you mention. I've just never thought of it in relation to what would happen with a shorter bullet. I'll be giving that idea a try.

  As for bullet wgt. in front or in back of center of form, I'm not an expert on this either. It's something that Dick Gunn will discuss with you at some length tho, and I think he's got some good points about it. Personally I just try to get the moulds I buy to work well. To follow the C of F idea you'd have to be ableto design your own bullets.... which is way beyond me. But, i am aware of the idea and resulting problems it can create. Your alloy idea tho might be an answer to the problem.

Volume & Compression

Been thinking that I should get some Starline brass and see how that works as I understand it has the smallest case volume. As I get it... from most to least volume it's Win., Rem., Federal, & Starline. Is that your understanding?

  I'll throw 2F & 3F powders strictly from the measure after it's set for the wgt. I want. I also check it every tenth throw to make sure things are ok. Powders like Goex have enuf fines and in the past have shown wgt. changes as you go down in the can. Swiss on the other hand has been pretty even from the top to the bottom. 1F is another story, and all charges get weighed. But even after dropping them thru a drop tube there is enuf variation in powder column hgt. that I have to make sure it's reasonably close before compressing. About .010" variation is best and anything more and I start to see unacceptable differences at the chronograph.

  Yes... I've run into this wgt. vs vol. thing with different lots of powder. The latest being Swiss 1 1/2. An old lot (bottle with no lot#) and a new lot with a lot # label showed a difference of 4 grs. between the old and the new for the same VOLUME. But, when I used the same WEIGHT, and didn't change any other setting on my dies (more compression), the MV's were the same, as were the SD/ES's and accuracy. Haven't figured that one out yet! I imagine tho that if the situation reverses with the next lot I will have to reduce the powder charge.

   I'm a great believer that a particular gun wants to be shot within a narrow MV range. Compression is important for maintaining a consistent flame front from shot to shot as it travels thru the powder charge. This also has a very short range that works well but doesn't seem to be as critical as the best MV. Actually it gets to be a balancing act to get both correct in order to get the best accuracy.

  Guess I better cut this one off to and start another message.

PETE

Hi Pete,

Perhaps I am going against accepted practice by using a hard lube.  However, what oracle decreed that only soft lubes could be used with black powder cartridges?  Let’s admit it, loading black powder cartridges after so many years of not doing it left all of us wondering where to begin.

Simplistic logic suggested that because there was fouling remaining in the barrel after each shot, we had to shoot a bullet with soft lube in order to deposit that lube in the barrel to keep the fouling soft enough to be removed by the next shot.  Since I’ve always wiped between shots, I’m not bound by that logic.  In reality, only the smallest amount of lubricant can be deposited in the barrel because the rearmost driving band of the bullet and any wads behind it will remove any surplus lube.

Is it the number of grease grooves and their depth that determines whether or not a bullet will run out of lubricant before it reaches the muzzle or the rotational velocity of the bullet?  There is a lot of linear and radial force working against the bullet at ignition.  I believe that a hard lube will have more of a tendency to stay put in the grooves of the bullet than a soft lube.  As I said in an earlier posting, it also helps prevent distortion of the driving bands because they can’t collapse into the grooves vacated by a soft lubricant.  I’m currently working with some hard lubes and black powder and initial results are promising but there is a lot more testing to do.  Remember, I’m the guy that shot paper patch bullets in silhouette matches when they said it couldn’t be done.  Either I’m simply too dumb to know any better or I’m an iconoclast.

feather

Good morning, Board;

I don't want to get in the middle of this good discussion except to question two things: (1) bullet hardness [temper], and (2) lube hardness with application to the bore.

(1).  Adjusting bullet hardness to the chamber pressure has become an article of faith to a lot of folks.  That's fine.  But to me, hardness is not nearly as important as consistency.  I shoot mostly 20-1 and 30-1 in black powder cartridges, but that's because it's traditional, it works and I don't have enough life left to try everything else.  Other hardnesses work, too.  Wheel weights work - easiest with a little tin to make them flow.

If adjusting the bullet hardness were so important, why do those funny looking yellow bullets shoot so well over such a large pressure and velocity range.  It's not the pressure of the load or hardness of the bullet.  The important thing is adjusting the load components so everything works together.

(2).  The lube reply really has two parts (I'm hung up on two parts today).  The first is how lube gets onto the bore.  I have seen everything from the lube grooves squeeze it out as the bullet slumps centrifugal force.  A .45-70 bullet spins in the neighborhood of 45,000 rpm - but only when it is well down the barrel.  When it starts, the rotational velocity is zero.  Rotation increases as the bullet accelerates so centrifugal force is not strong in the first part of the bullet travel in the bore.

Another idea I have seen is that minute variations in the bore cause the bullet to expand and contract slightly as the bullet travels and causes a "pumping" action.  This one I buy the least.

Now, to the point.  I believe lube is applied by simple inertia.  As the bullet accelerates at the rate of many many times the force of gravity, the lube is forced into the bottom of the grooves by its own inertia and tries to flow between the side of the bullet and the bore.

Harder lube would be less inclined to flow, but I have no idea at what point that would make a difference.  I believe that the soft BP lubes are effective not so much because they are soft, but are soft because of their composition.  A lot of folks adjust their lube formulas bacause they think one consistence works better in one kind of weather and so forth...  Again, I won't argue the point.  I just don't adjust mine.

The point was advanced that lube application to the bore was not important because the bullet base band and the following wad cleaned the bore.  I disagree.  If you place grease on a smooth surface and try to wipe it off with one swipe of a towel, you leave some of it behind.  In fact, you can work pretty hard to wipe grease up with only towels and it will be a long time before the surface is clean.

That lube film is important.  With conventional BP lubes, the remaining film is a fat.  The BP residue is alkaline (basic).  When you add moisture with a blow tube you get ...... ready for this?....... SOAP.

That is why BP lubes are made of organic fats instead of petroleum greases.

Of course, if you clean everything from the bore for each shot, the kind of lube is not as important.  If you clean everything from the bore.........

I apologise for running overly long, but I'm feeling much better now!

Y'all be good.

horsefly

Good morning, Pete;

You mentioned that these discussions are good at helping learn something.  One thing that I keep failing to learn is how careful I need to be to keep from sticking my foot in my mouth!  As I remember, I said that I didn't think one lead hardness per se was better than another.  As you point out with nose slumping, there are limits to the hardness thing.  If the bullet is soft enough that you get uneven slumping, then it is too soft.

But let's look at slumping for a minute.  It's not all bad.  Slumping is a plastic deformation caused by a conflict between the forces of acceleration on the base of the bullet and the inertia of the lead - the tendencey of the bullet to remain at rest.  Movement of the base of the bullet is resisted by the mass of the entire bullet.  Half the way up the bullet, its movement is resisted by only half its mass.  The point being that as you move from the base of the bullet toward the nose, the tendency to slump becomes less.  Slumping is most obvious just in front of the front driving band.  It is also what cases the base of the bullet to swell and seal the bore.

{NOTE: I don't intend to insult anyone's intelligence.  Most of the readers here know exactly what I'm talking about, but I always try to write this stuff so that folks less familiar with the ideas can also know where we're going, too.}

So, I maintain that slumping is not necessarily bad.  The bad part is UNEVEN slumping.  As you rightly point out, many moulds are too small on the "bore riding" section and can slump non-uniformly.  They don't shoot worth a hoot.

If the bore riding section is very near bore diameter, the non-uniformity will be much less and other things being equal those bullets should shoot better.  The "DD" bullet moulds designed by Dr. Mann (I think) and made by NEI have a small ring around the nose to center the bullet in the bore so the bullet will slump uniformly.

So, going the long way around, I agree with you the bullet needs either to be hard enough not to have the nose slump or the bullet needs to be good enough that it will slump uniformly.

I do still believe that a 19 to 1 bullet has every chance of shooting as well as a 23.5 to 1.  there is no magic mix.

The other thing I want to pick up is purging.  I am a barefooted pilgrim on this subject.  I don't know that I have ever seen it - that may be because I just don't look for it.

Your observations over the chronograph are very interesting.  The thing that really caught my attention was this statement: "This purging even happens when you wipe out between shots with BP, and when shooting smokeless."

As I read your description, one bullet establishes the condition and the next suffers from it.  If the bore is well wiped between the shots, how is there a lube buildup to bother the next bullet?  Beats the heck out of me and I look forward to the rest of the discussion.

Let me tell a story about visiting a bullet casting and reloading operation one time.  Their product was bulk pistol bullets and reloaded pistol cartridges with their own cast bullets.

As we got to the bullet seating station, I noticed that the bullets only had the lube grooves about half full.  That is each groove had some lube and some space.  I asked the fellow about these bullets and he told me that their bulk bullet sales always were lubed with the grooves full.  Otherwise, the customer thought there was something wrong.  HOWEVER, the bullets that they loaded were only half lubed because they "shoot better".

There is a lot to learn about this lube stuff.

Y'all be good.

horsefly

Is it possible that by leaving the front grease groove or grooves empty, the bullet shoots better because the bullet bumps up more, thereby filling the rifling better for a more uniform seal?
Keep on hav'n fun!

MikeT,

  I don't believe so. If your bullet is properly sized....  .001" to .002" over groove diam. ....... there shouldn't be any bump up involved. In fact, just the opposite. If the alloy is to soft and you leave lube out of the front groove, the groove is going to slump, and I think everybody agrees that ANY slumping that can't be completely controlled is not good.

  But, I dont want to rule out your idea entirely. The Lyman 457125 I mentioned up the thread a ways might prove your point. If I leave one groove empty accuracy improves over all groove filled. Leaving two grooves empty I get the best accuracy. If I leave three grooves empty accuracy goes down hill and is worse than having all grooves filled. Has a point been reached where slumping is occurring in the groove(s)? Should I go to a harder alloy and try it again?

PETE