Browning 1886 carbine Year 1992 45-70 Lack of accuracy on 100 meters

[bigbuck]

Dear all,

you may give me a hint regarding the following:

My load was a 340grain boolit with 17grain trailboss.

I did 20 rounds and 15 have been in a circly of 1 inch :-D, however 5 shots ruined the group..to a circle of 4 inches:oops:
This appeared not at the end but like shot # 3, 6, 9, 12, 16.


Could it be that my load is very close to subsonic at 100 meters - and some are above and some are below subsonic near the target?

What else could it be? Pls advice


greetings from Bavaria

bigbuck

[NSB]

I have had poor results using Trailboss powder. At the low velocities you're shooting at you will get tumbling at 100yds which will create very poor grouping. I'll bet some of your bullet holes on the target aren't nice and round when you look at them. You should also slug your barrel to make sure your bullets are of the correct size for your bore. You should be a little over bore diameter for best results. You'll probably find that a heavier bullet will also shoot better. I got much tighter groups when I went from the 300-350 grain bullets up to a 405 grain bullet. There are many, many more factors involved in getting your gun to shoot but you might want to start with these. FYI, my better powders for light loads in my 1886 were achieved with 5744, 2400, and 4759 powder and a bullet velocity of around 1200-1300fps. Hopefully some others will add to my limited knowledge and offer some further advice. Good luck and don't give up. My gun will shoot right around and inch on a day where I can do my part.

[Scharfschuetze]

Actually, a four inch group (10.16 cm) is OK for a 20 shot group using a 45/70 from an 1886 Winchester at 100 meters (109 yards). I usually base my accuracy results on 10 shot groups and many here use a 5 shot standard. 5 shot groups may lie to you as to their accurcy, 10 shot groups are usually sufficient and a 20 shot group will tell you the truth!

As NSB asks above, check or slug your bore and then size your projectile .002" above that. At a guess, .459" or .460" should work well in your modern Winchester and get the most out of your bullet's usable accuracy. Of course an adjustment to your powder charge may also help. Can you get other powders in Bavaria? My most accurate 45/70 loads are made with a 405 grain (26.243 grams) cast bullet.

Where in Bavaria do you shoot?

Ich wuensche Dir viel Erfolg mit deinem Gewehr!

[runfiverun]

if the flyers come at regular intervals [every 3-4-5 shots] I would suspect the lube being too wet.
it builds up and purges at regular intervals like that.
the browning 86's also have tight throats, so you have to watch the shape and length of the bullets nose as well as the front drive band hitting the rifling when chambering.

[bigbuck]

Dear all,

Thanks for your kind replies.

Here my notes:

- All bullet holes were perfect round
- i am going to try 405 grainers as well
- there is no front drive band hitting the rifling i cecked this (space is approx. 0,02 inches ogivale to the rifling)
- lube builds up -next time i will swap after each shoot with a dry patch
- sure there are many powders available but TB was on hand...
- i am close to Augsburg located

Greetings

bigbuck

[Ninety Caliber]

bigbuck, this will sound crazy, but try 13 grains of Trailboss under a 405 gr. that's my load up to 200 yards in my 1895 Marlin Cowboy. Shoots aprox 950 ft per second but groups about 3" at 100 yds.

[bikerbeans]

FWIW, My best TB loads with cast in the 45-70 came at a powder density of around 90 to 93 percent. The best bullet in my rifle (it was a 1:20 twist handi rifle, 22" barrel) was a Lee 405g HB at .460". Muzzle velocity was in the mid 1,200 fps range.

BB

[bigbuck]

Hello and happy Christmas,

Thanks for your hints. I will start a loading ladder with your recomendations and see what will happen

Greetings

bigbuck