Crazy stuff with annealed gas checks

[44man]

I chronographed the annealed checks against the hard checks in my 45-70 BFR and found some real strange stuff. I used the same load for all. My first was with dacron filler over 31 gr's of 4759 and a LP mag primer. It was real bad as far as the chrono goes;
SD 56.9, MAD 37.7, ES 138.1, AVE 1229.4 fps
I had three that had real bad runout and I didn't catch it right off. I didn't flare enough to start the boolit. I marked them just to shoot away. I fixed the other cases. BUT, my first 5 went into 5/8" so I shot the bent ones too. Those three hit low left but went into 7/16"?????? Thats the left target.
The velocity baffled me as it is 325.8 fps slower then a hard check.
I then tried them with no filler and the first shot was only 982 fps and the gun was full of unburned powder. I edited it out. The rest were;
SD 41.5, MAD 29.2, ES 96.5, AVE 1315.1 fps. I should have left the bad shot in. Thats the middle group. I never had this bad with a hard check with no filler before and never seen a difference between filler and none.
I then went to the hard check and got this;
SD 9.1, MAD 6.5, ES 23.8, AVE 1555.2. Still lower then normal that I can't explain except for the temperature outside. I usually get 1632 fps. Recoil was back up there and I was having trouble with the butt on the bags so I got some stringing. Thats the right target.
The only thing I can make of it is the annealed check has less friction and is leaving the bore too fast to burn the powder. I had very tight case tension and a good crimp. How do I ever explain the group I got with 138 fps difference?

[Newtire]

Hi .44 man,
How far away were the targets?

[Bass Ackward]

How do I ever explain the group I got with 138 fps difference?


44,

I ain't going to tell ya I got the answer. But I can answer this question above. Actually Lloyd was trying to tell you about this the other day. And this is part of the heavy bullet discussion in another thread. What is considered short, for a barrel, is a relationship of case capacity to bore diameter issue that limits powder choice because of burn rate. ESPECIALLY, when you don't have a shoulder to help burn it. A 50 with a 4 5/8" barrel may have more flexibility than your 45-70 with a 10 as long as you want to stay with buttons in that caliber. :grin:

You don't have barrel vibration on a handgun to worry about harmonic nodes or bedding, so at short enough distances you should group if your holding the gun. Now, should you move that on out, it will become apparent. Using your own logic, you don't take an 8" gun off of a battleship and shoot 50 yards with it.

Now if you added bullet weight, you might get a completely different result or not be able to notice if checks are soft or hard. Could be you are on a cusp. That's what I call the TZ.

[MT Gianni]

Interesting results indeed. I only anneal checks when the mould throws a boolit that has a large base making it hard to seat. All test results are then done with annealed checks and that boolit. I probably should flare some and compare loads. We are back to checking every component again instead of trying to find an easy way. Good luck in your search 44man, Gianni.

[44man]

Now all of you know I don't shoot closer then 50 yd's and thats how far I shot. Thats why the bad load drives me nuts. I guess I need crooked loads and poor powder burn.
I have a heavier boolit to play with but still need to design a real heavy one. I still want a WFN for hunting. Does anyone have a similar boolit that shoots good? All I need is a picture posted and the weight of the boolit.

[45 2.1]

Now all of you know I don't shoot closer then 50 yd's and thats how far I shot. Thats why the bad load drives me nuts. I guess I need crooked loads and poor powder burn.
I have a heavier boolit to play with but still need to design a real heavy one. I still want a WFN for hunting. Does anyone have a similar boolit that shoots good? All I need is a picture posted and the weight of the boolit.

SR4759 needs a good deep, not mashed in, crimp for it to burn correctly. When you get it right, it sets up and produces really good groups. As for a good picture of a light boolit, look at post #8 (E-mail me if interested) on the thread by Springfield about a 300 gr. Biglube boolit in the Group Buy forum. Its pretty close to what your wanting.

[44man]

Interesting boolit but I think I want to move up to at least 400 gr's. (Did I look at the right post?) I looked at the LBT boolits and the 425 gr looks interesting with the .374 meplat. I think I will have to draw one up with a PB.
My problem has been time this year, I just can't get ahead. Testing has fallen behind and I never made a BPCR shoot. Just too much work around the house.
I can't figure where the year went and it is close to archery season already. I still have venison from last year in the freezer.
Is this what old age does?