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Question about sighting in a BBF
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I just got a Kreighoff BBF from Germany. It is 12 gauge over 7x65R.

1st shot was near the bullseye and the 2nd and 3rd shots were 5-6 inches high but touching.

I let the gun cool down and the same thing happened on the next 3 shots.

Is this normal? Scope is in the claw mounts tight. I would tend to believe the scope is not the problem since the issue is repeatable.

Thanks
 
Posts: 26 | Registered: 08 October 2018Reply With Quote
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The second and third shots being higher is normal. The Germans call this "klettern" or translated roughly as climbing. This occurs due to thermo-dynamics. The heat generated by the first shot causes the barrel to expand on the lower surface more than on the upper surface where the rib absorbs the thermal load causing the upper surface to be cooler and expand less. This will happen with all double barreled weapons with a rifled barrel(s)and a solid rib. In your case it seems a bit extreme. I also have a Krieghoff BBF and the second shot climbs about 3/4 inch and the third another 1/2 inch. I can adjust the scope or simply adjust my target.

Try several different loads. These break open guns often shoot best at modest velocities. What caliber is it?
 
Posts: 1135 | Location: MN and ND | Registered: 11 June 2008Reply With Quote
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The facts of this type of hunting arm are perfectly described by JON in the post above.

The key is to practice always hold lower for the second, and third shots till the barrels cool!

Combo fire arms have a set of rules all their own!
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Posts: 14573 | Location: TEXAS | Registered: 08 June 2000Reply With Quote
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The caliber is 7x65R. I am shooting 150 grain handloads at around 2,800 FPS. My friends Heym BBF did not do this today with S&B factory ammo.(his is also a 7x65R
 
Posts: 26 | Registered: 08 October 2018Reply With Quote
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I'll add to this that conventional drillings walk up and usually to one side.

When doing bench work and working up loads I have several cans of starting fluid along. I take the barrels off and wood off them, then I spray them with ether to cool them off. I give them a light oil coat afterward.
 
Posts: 1765 | Location: Northern Nevada | Registered: 27 February 2004Reply With Quote
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Your gun seems to walk quite a bit more than I have experienced. Try a load at 2650 ft/sec and see if you climb as much. This caliber was really intended to shoot 160-175 grain at moderate speed. It is really a 280 "light", mild recoil with good penetration. The BBF is usually used on stand with most shots being under 75yds. A 7mm along with a 16 ga. slug is the norm and very effective.
 
Posts: 1135 | Location: MN and ND | Registered: 11 June 2008Reply With Quote
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quote:
Originally posted by JonP:
Your gun seems to walk quite a bit more than I have experienced. Try a load at 2650 ft/sec and see if you climb as much. This caliber was really intended to shoot 160-175 grain at moderate speed. It is really a 280 "light", mild recoil with good penetration. The BBF is usually used on stand with most shots being under 75yds. A 7mm along with a 16 ga. slug is the norm and very effective.


I couldn't agree more. I load my Kreighoff Trumpf Dural drilling 7X65R with 156-160gr pills at 2,675. It thanks me for several reasons. I'm not hammering that hinge pin hard, and it shrinks to well under 1" five shot groups with cool barrels.

The 7X65R is designed to shoot like a bolt 7X57 with warm loads. Wink
 
Posts: 1765 | Location: Northern Nevada | Registered: 27 February 2004Reply With Quote
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Thanks for the feedback guys. I have some 173 grain S&B I can try and I also ordered some 175 grain Hornady Elx’s to try.
 
Posts: 26 | Registered: 08 October 2018Reply With Quote
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Remember the gunbearer's comment in Green Hills: "one shot meat, two shots maybe, three shots heap sh*t!" My BBF has the rifle barrel on top--a Brno ZH-204 with 7x57R over 12ga. It does jst the opposite of yours: first two shots tight, then 3rd shot down and fourth shot way down. Gotta hit 'em with the first one!
windy
 
Posts: 39 | Location: far from God's country | Registered: 14 February 2008Reply With Quote
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I've been very fortunate in that my 12ga/7x57R will put the first 3 shots into 2 inches at 100 if I shoot them in quick succession. Fourth shot goes really high, 5 inches +. It will also tend to shoot high after the second shot if I shoot slowly. If I cool the barrel between shots I have consistently gotten sub-inch groups, but honestly that has little to do with field use, it's just nice to know. I've also found that the tendency to walk-up is less in extremely cold weather.

I think finding the right bullet and velocity is the key, I experimented with about every 7mm bullet I could and several different powders. I finally just bought several brands of premium 7x57R brands of factory ammo, carefully chronographed each one and did multiple accuracy tests including one shot let it cool groups as well as seeing when and how badly the rifle began to "walk-up". The winner was 156 grain Norma factory ammo. Hellishly expensive stuff! Anyway, I then limited my experiments to bullets in the 150 to 160 range and a velocity matching the Norma ammo, 2650 fps. Norma Oryx bullets were excellent but flat base Hornady 154 gr. were fantastic (sub MOA with cool barrel) Norma powder was either not stocked locally or quite expensive via internet sites. Looking for a substitute I found H-4350 proved to be ideal.

Once I established a good load for the rifle end of things I started experimenting with slugs with the idea of having a short range double rifle. About this time I ran into someone who had the same make and model of gun I own (Antonio Zoli exported and sold in Germany by Hebsacker et. al.) According to him the gun was factory regulated to 150 gr loads and Brenneke slugs. I ordered all the flavors of Brenneke slugs I could find on line and shot them at 50 and 100 yards until I found one that was accurate and more importantly shot to the same point of impact as the rifle load. I found two types more than exceptable with consistent sub 6 inch groups at 100. (Even had a 2.5 inch 3 shot group once.)

Over the 9 seasons I've had the gun it has take a multitude of big game out to 300 yds. I've also had several days where I took birds, including ducks, and deer or antelope. This year I had my third 1-2 with whitetails killing two does in very quick succession.

These type of weapons are fantastically versatile as well as aesthetically pleasing companions in the field, however; they may entail a bit more effort to get their full potential than many people realize.
 
Posts: 763 | Location: Montana | Registered: 28 November 2004Reply With Quote
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Thanks for all your input. I now realize I have to take a whole new approach to load development for these guns. I have been loading for custom hunting rifles for years and have never had an issue getting to an accurate load.

These cool guns are different and my goal is now minimal poi change on a 3 shot group vs a ragged hole at 100 yards.

I have another kreighoff on the way from Germany so I need to get it figured out.

I will report back once I test my 175 grain loads.
 
Posts: 26 | Registered: 08 October 2018Reply With Quote
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I think you learned the same thing all of us who shoot drillings and combination guns have learned. Sure came as a surprise to me also but, I learned to make it work and you will too.


Jesus said, "I am the way, the truth and the life. No one comes to the Father but through me". John 14:6
 
Posts: 219 | Location: Northern Missouri Ozarks | Registered: 13 February 2016Reply With Quote
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I am getting closer. The 175 grain hornady loads only jumped a few inches. I am going to try some 162 grain bullets at 2,600 FPS this weekend.
 
Posts: 26 | Registered: 08 October 2018Reply With Quote
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I have a 7x65r BBF. Does exactly what your does. However it does like a 173 gn bullet over 50gr of IMR4350. These shoot very accurately from cold barrel. And close enough for a quick 2nd shot if needed.

With mine I concentrate hard on making first shot count. And if you take your time then you have no issues. Also BbFs are quite light and in 7x65 have enough recoil to expose poor shooting technique. You need to control the recoil by a firm grip on the foreend - think double rifle technique rather than bolt actioned bipod equiped varmint rifle.
 
Posts: 822 | Location: Scotland | Registered: 28 February 2011Reply With Quote
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quote:
Originally posted by 243ackley:
I am getting closer. The 175 grain hornady loads only jumped a few inches. I am going to try some 162 grain bullets at 2,600 FPS this weekend.


I think you're right on track.
 
Posts: 1765 | Location: Northern Nevada | Registered: 27 February 2004Reply With Quote
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Oh, Heym's post reminded me of what may be a quirk with my rifle, unfortunately don't own enough BBF's to know if it's universal. Anyway, if I rest the fore-end on my hand, and grip it firmly while shooting accuracy is consistent. However; if I rest the fore-end on a sandbag groups go to hell! If I'm shooting in the field and take a shot prone or seated off sticks I rest and grip the fore-end with my hand and everything is fine.
 
Posts: 763 | Location: Montana | Registered: 28 November 2004Reply With Quote
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Paul,
I have experienced the same situation with my Sauer BBF. So you are not alone. I was trying to zero a scope off of a rest and could not get consistent results. Once I held it firmly in my hand which was on a the rest I was able to get consistent. Interesting for sure. Not at all sure why this happens. Anyone have any ideas?
Mike
 
Posts: 12 | Location: ohio | Registered: 17 August 2013Reply With Quote
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Sure

It's not complicated. Recoil starts when the bullet first moves, not when it leaves the barrel. That recoil also moves your body and hand, but it has varied effect on a stationary sandbag that stays stationary sometimes and moves a bit at others.

The total body movement from holding the rifle is more uniform.
 
Posts: 1765 | Location: Northern Nevada | Registered: 27 February 2004Reply With Quote
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Never had that problem with my BBF97.

https://youtu.be/bfyfLvp6QqA
 
Posts: 153 | Registered: 24 July 2010Reply With Quote
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My 7x57R over 12 ga is good for 3 shots then goes to hell until cooled. S shots into 2 inches at a 100.
It places rifle and slugs together at 30 yards
 
Posts: 16942 | Location: wis | Registered: 21 April 2001Reply With Quote
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