Shooting and Rocket Fuels

Fast is our business

45 Caliber

For several years the only caliber offered for smokeless muzzle loads was 50. That mirrored the choices made for black powder (BP from now on) rifles. The overwhelming number of components and supplies for BP rifles come in 50 caliber. That choice was made due to the needs of BP shooters.

The needs of smokeless shooters are entirely different items. If it’s not been explained, then suffice to say, BP (or subs if you use them) does not work like smokeless. The energy of BP is restricted because it’s ability to change burning speed  is limited. Also the smoke would tell you much of the powder is still solid (and visible) after the shot. So it changes to gas much less efficiently than smokeless.

No attempt will be made to explain BP shooting but it has to be stated not enough energy is had by lighter weight bullets at distance with BP loads. That’s one reason often given to neglect smaller calibers. The truth of it is not our debate. The only statement needed is: that’s not a problem in smokeless shooting.

The real reason smaller calibers were considered was recoil. As mentioned in the page on pressure speed was not a problem. However it came with recoil. A 50 caliber smokeless muzzle loader can be more powerful than a 375 Holland (yes with a safe pressure) but have you ever fired a H&H? 300 grain bullets over 2500fps are not mild. In fact they may rattle your teeth.

In an effort to shoot a lighter weight bullet (and save recoil) the 200 and 195 grain 40 caliber bullets were tried in 50 caliber rifles. None of the attempts were very successful. From the effort a constant appeared. It took on the name “Rick’s Rule”. That is: “if the bullet is less then .060” the bore diameter it will be very difficult to shoot to speed accurately using common sabots and components in a smokeless muzzle loader”.

 

 

From left to right the bullets weigh 400, 350, 300, 250, 200, and 180 grains. Shot to normal speeds for weight which produce more recoil?

Lighter weight bullets take advantage of aerodynamics as well as reduced recoil. However this only works when changing to a smaller caliber. In the same caliber shooting a lighter bullet does reduce recoil but a light weight bullet is a brick in flight compared to a heavier bullet of the same caliber. The light bullet can’t hold momentum as long. However if the light weight bullet is also smaller in diameter it has less frontal resistance. A 200 grain 40 caliber bullet has about the same flight characteristics as a 250 grain 45 caliber bullet. It also produces 25% less recoil at any speed.

Our goal here is to shoot with a greater speed but not increase recoil or reduce downrange effectiveness. It’s already been said that was hard if not impossible in 50 caliber. So why not shoot  a smaller, say 45 caliber, bore? Now before you say “it’s been tried” remember that was with BP. Whatever reason or objection you had with a 45 caliber BP rifle it does not apply with smokeless shooting rifles.

  You’ve heard said, light weights can’t be fired fast enough to take advantage of the speed. Shooting smokeless they can. Bullet speeds of 2600 to 2800fps with pressure low enough to ensure sabot performance are easily available. That’s plenty of energy for deer sized game past 300 yards. And it can be done with a normal length (24 or 25 inches) barrel. You could go faster if you like but there’s that word again: recoil. Why reintroduce it into the equation?

A summary would conclude: You can have faster bullet speeds with equal or even less recoil while shooting a bullet as aerodynamic as the one commonly shot in a larger caliber. Sounds like it ought to work: and it does.

One more advantage is had with going to a smaller bore. That concerns the performance gap that was mentioned in the page on pressure in a 50 caliber rifle. There it was shown between 45 and 60 grain loads no powder was the correct burning speed to be useful with common weight bullets. In 45 caliber pressure is easier to build. As long as it is held within limits that’s actually an advantage. It means that starting at 55 grains and going up there are many common rifle powders that provide excellent pressure properties from 55 to 75 grain (or more) loads.

For a 50 caliber rifle we mentioned 3 factory powders, then a big skip, and three more suitable powders. Shooting 45 caliber the common 195 or 200 grain bullet Reloader #7, and H4198 work between 55 and 61 grains. Between 60 and 70 grains, VV N130, Alliant 10X, H322, Xmr-2015BR, and Benchmark all will provide useful loads. That’s 8 powders in a 15 grain spread. The 45 caliber smokeless is very easy to load.

The proof of a concept is how well it works. To provide some idea of how less than 50 calibers might work I’m going to provide some targets.

The one on the left was shot by my friend Dave Daub. The rifle was a Remington 700 converted to smokeless muzzle loader. It has a 45 caliber Pac-Nor barrel 1 in 22 twist.

All the pertinent information is supplied with the target. This 62 grain load of H4198 gets the 195 grain Barnes bullet to better than 2600fps.

More important is the three shots are less than 2 inches apart at a distance of 300 yards. There have been times when a group this size would impress if shot at a third the distance.

This is not the only rifle that shoots to accuracy at range. The smaller calibers provides accuracy in other ways.

This target is a three shot group also fired by Dave Daub. The distance is 200 yards as noted on the target.

The 56 grain load produces just short of 2600fps. Even though the speed is not terribly fast that would have little or no bearing on the load’s effectiveness.

The rifle in this case is an Encore that looks very much like the one seen at the bottom of the home page. The only differences would be the barrel has no iron sights.

When you start to have less than MOA (minute of angle) accuracy at 200 yards and farther with a muzzle loader it’s something to write home about.

The two targets shown here mean that Dave could spend considerable time corresponding if he were to take the notion.

The target to the left is my own production. It was shot using the Savage 10ML rifle that can be seen on the home page of this site.

The load is 67 grains of H322 under the 200 grain SST 40 caliber bullet. The sabot is a Harvester baby blue model and the load was set off by a CCIm 209 shot shell primer. At 2700fps it is moving on but the recoil is still mild compared to even an average load for a 300 grain bullet.

Accuracy is 1.2” for the five shot group and that would not make many envious. However the group was shot with only a marginal rest. Even with a fair amount of shooter error accuracy is better than average.

If shot with a lead sled or other mechanical rest there is little doubt this rifle will shoot five shots well inside an inch at this 100 yard distance. With four shots within an inch there’s no need to do much explaining.

The point was to show 45 caliber smokeless rifles work. The point is made and much more could be supplied to make it with certainty.

R = (V bore + V case)/ V case

In another area of this site there is a section on shooting bare copper jacketed bullets. By general use this has come to be called “sabot-less” shooting. The 45 caliber rifle is a natural choice for shooting bare copper bullets in this manner.

The system relies on the fact that 45 caliber muzzle loader bullets are actually the size of a 45 caliber pistol bullet (.451” in diameter) while the bore of a 45 caliber rifle is the normal rifle size (.458” in diameter). The .458” diameter is the largest part of the barrel called the grooves. The smaller dimension of the barrel is actually .008” less than the groves at .450”. The small diameter is called the lands.

It should now be obvious 45 caliber jacketed bullets commonly shot in sabots are almost the same diameter as the 45 caliber barrel lands dimension. Some barrels are even slightly oversized making a match of .451” even closer. With a dimension tolerance of .001” for the barrel and a smaller but real tolerance for the bullet I’ve seen 45 caliber barrels where a .451” bullet will start and go straight down to the bottom with no modifications. 

These three images show the correct choice of caliber and size will allow a copper jacketed bullet to fit snuggly without a sabot. Only two of these barrels are 45 caliber. See the page on smaller calibers for details.

For details on “sabot-less shooting and bullet sizing see the “Shooting Bare Copper Bullets” page in this website.

Expansion Area

Behind this page is an article on building a smokeless muzzle loading rifle. The only entrance to the page is if you click here!