CHP 9 The first 40 caliber rifle

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RBinAR

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Today I finally got to get some serious range time in shooting the 40 caliber conversion rifle. I finished the rifle last week but time to get to the range has been a problem till now.

The first load out of the rifle was chosen as a mild safe starting point. It was the 200 grain Shockwave bullet, CCIm primer, and 44 grains of H-4198 powder. The 405 Winchester shoots nearly this amount of powder with a 300 grain bullet at only 42,000kpsi pressure so I thought it to be a mild place to begin.

The first few shots confirmed my thinking on the pressure. Primers were pristine after firing and the recoil target impact and barrel fouling all were in accord with what any other 10ML style rifle would present. I thought this load would shoot to about 2300fps and my timer averaged three shots at 2289fps so that was well within my comfort zone as well.

An image appears below this paragraph of the accuracy I was getting with this load. The five shots seen are the first five shots ever shot for group out of this rifle. They could be the first five for this caliber and style of shooting from any rifle. As you can see the group measures about 1 5/8? center to center. The target grid shows about a 1 ? to 2? group but don?t let that fool you, the target was printed with a slightly undersized printer setting.
40cal.jpg


I don?t think these results are that bad considering the wind was 20mph and gusting to more than that. It was so bad that I had several shooting materials blown into the range so far they are beyond finding. The only shot that appears out of group was a called vertical flyer.

I will be adding a few details and images as time moves forward but these are need to know facts. I had to knurl the bullets. The barrel fit is good but a little loose for a smooth sided bullet. By taking two files and putting on a slight knurl I was able to get a perfect sabot like fit with no worry of the bullet causing poor ignition or sliding around with rifle jarring.

I shot these loads using my normal practice of a 1/8? fiber wad as a buffer. I didn?t have any 40 caliber wads so I simply made a punch .415? in diameter and took 50 caliber wads and punched them down to size.

The 40 caliber bore needs a special loading and cleaning jag. The size of the jag is so close to the rod size this presents a few problems with dry patching (if you do that kind of thing) between shots. I believe it would be possible to use a regular 3/8? rod with a few grooves cut in the end and an inlet for pointed bullets to do away with the jag completely. Whatever the case using synthetic patches greatly decreases the chance of getting the patch lost in the barrel.

Before I left the range I tried a load of H322. It has the same base components as above except the powder charge is 53 grains (don?t shoot H-4198 to this level). I expected this much powder to increase bullet speed about 100fps with the same pressure. When three shots averaged 2392fps I felt things are proceeding normally. The accuracy of this load wasn?t great but all shot hit within 2? and all the holes were round so it looks as though it is simply a matter of tuning to a speed the rifle likes.

sw40-copy.jpg


While shooting the 40 caliber smokeless muzzle loader I had considerable help deciding on a load. Notably there are some pretty good sources for the 405 Winchester which is very close to the caliber we?re shooting.

The only problem is the lightest weight bullet normally shot from Teddy?s caliber is 300 grains. Still with this information it was possible to gain an idea of what will work within the pressure limit required.

The following is what was discovered with three particular powders. All components were the same with every load. The bullet was the 200 grain Shockwave, the primer was the CCIm, and I used a 1/8 fiber wad.

H4198 proved to be useful with loads of 41 to 45 grains. The maximum bullet speed was 2320fps.

H322 worked with loads from 50 to 54 grains. Bullet speed at maximum load was 2488fps.

Benchmark loads range from 58 to 62 grains. Bullet speed at maximum load is 2687fps.

From what can be seen here is the normal course of a smokeless muzzle loader. However the effect is faster in this caliber than in a larger bore. Notice that as you change powder speeds and load maximum go up in a fairly linear rate.

Using that profile it would not be hard to predict that slower powders will work in much the same manner. If we go to H-4895 load limits will probably go up about 4 grains. Moving even slower Reloader 15 or Varget would make about 70 grains. With each step bullet speeds could be expected to go up 100 to 125fps. So I?d expect 70 grains of powder to shoot 2900fps.
 
RB, Your results today are totally encouraging. Congratulations, and I'm looking forward to hearing more as you proceed with your testing.
Ridge
 
:D Reads like things are going great! A 1 5/8" gp in strong winds is outstanding.
Corvair, hello, the rifle is in a stock, black, bedded and now re-bedded and soon or already 3rd pillared stock that I am considering having Armor clad in a camo pattern ( primarily since I plan to use the gun for varmint hunting where most shots early in season are quite close). Likewise, I am considering having a SSS muzzle brake installed, primarily for noise containment. Being primarily a bow hunter(1st bow deer in 1957 in AR - last bow deer and bear 2006 in AR :D ), I deer hunt in AR only during our very short 2 week-end,3 Christmas day seasons and then it is mostly beanfield hunting where max range is an advantage. Last three deer shot with smokeless MLers were 108,132,252 yds. My understanding is that now 40 cal and below MLers are again being legalized for varmint hunting as well as being the minimum caliber for deer. IOWs a 40 cal is just pretty good for Arkansans. I think a few other states have the same advantages.
 
I LIKE it, I LIKE it! 8)

I'm thinking you better hire an assistant! You're gonna be covered UP! But then you are all ready.. :lol:
 
Obviously this is Steve's rifle?

Boy o boy Steve, you sure are going to have a sweet one when the rifle is finished! :D
 

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