17 AH erratic performance

[Fred W]

  I have a Contender,  Bullberry 22" bull barrel in 17 AH, 10" twist.  Have shot mostly Berger moly 20 grain bullets, recently tried 20 grain Vmax.  Some groups have been pretty good, but typically it will put 4 shots in or near one hole, then they start to wander.  Extreme example:  yesterday after a barrel cleaning the first V-max went clean off the paper, followed by 4 in 1.15".  I gave up for the day.  I realize scope might be suspected, but it's a Unertl target scope that was recently back to the factory for power change and I have been over and over the mounts.  Loads have been checked for runout, I load with bullets touching the lands.  I've used 1680, now using N120.    All suggestions welcomed!

[quicksdraw45]

Is it always the first couple of shots out of a clean barrel ? some barrels need a couple of fouling shots , Or is it a vertical string and needs the forend free floated ? . Have you tried letting the barrel cool between shots ? I dont shoot the contender in rifle form but I do in the pistol ,I also have a encore rifle and NEF that are both break action rifles and I have found that they are kinda picky about how the sit on the bags and prefer the front bag to sit right in front of the trigger gaurd .  I have also found that the amount of pressure applied on the stock by the right hand (right hand shooter) will affect groups.
In my opinion the break action rifles are a little harder to shoot than a rifle with a full stock .

[Fred W]

45, thanks.  I will try the bag near the trigger guard (I'm using el cheapo Hoppe's bags, better than old sox I guess).  As for barrel heating, the 17 AH doesn't seem to put out any noticeable heat and recoil is pretty slight too.  I've had few problems shooting the same setup with a TC factory barrel chambered for K-Hornet, so it does seem to be mainly a 17 AH problem.

[Javelina]

Hello Fred W,

The 17 AH from Bullberry is a VERY accurate barrel.  If you've checked your scope and scope mounts you might want to consider the following.

1.  Use SMALL pistol primers.
2.  Uniform your primer pockets.
3.  Ensure uniform length by trimming cases.
4.  Determine chamber length and try loads starting at .005" off the lands and then increase that distance until a sweet spot is found.
5.  If you're not using H-4198, you might try it.  Start around 10.0 grains and work up in .2 grain increments watching for pressure signs until you get to around 10.6-10.8 grains with Hornady 25 grain hollow-points.  I found best accuracy at 10.6 - a really mild load, but great accuracy and terminal performance.  If you prefer lighter bullets, use a Hornady 20 grain ballistic tip bullet working up from 10.0 grains of H-4198 to around 10.8 grains, watching carefully for pressure signs - the Bullberry chambers are fairly tight in 17 AH, so you can't use load manuals like Saunders' with any degree of confidence for the 17 AH in Fred Smith's barrels.  Bullberry chambers in 17 AH just can't take the higher pressures.
6.  Index your cases by making a file mark on the rim that you can see from either side, both when the cases are in your reloading tools (put them into the shell holder the same way every time), and also when you place the case in the chamber (I center the mark on the extractor every time).  This ensures the maximum amount of uniformity you can achieve without neck turning (a real bummer in the 17 AH - they're just so small!) during the reloading and shooting process.  NEVER discount indexing to reduce your group size noticeably!
7.  Weigh every powder charge with a known good scale.
8.  When seating your bullets, start with the index mark toward the left side of the insertion slot in the shell holder, seat about 1/3 of the bullet, rotate the case about 1/3 clockwise and seat another 1/3 of the bullet, rotate until you can barely see your index mark on the right side of the insertion slot in the shell holder, seat the final 1/3 of the bullet.  This stops many of the concentricity (run-out) problems for me.
9.  If you're not using a hangar bar on your barrel, I highly recommend it.  You can also glass-bed the hangar bar into the forend using Marine-Tex, I have done this on all my barrels with SUPERB results.
10. If your trigger has not been reworked by a COMPETENT professional, have it done!  It makes a world of difference.
11. I agree with most here that the hinge-pin is not generally a problem, but I have found on two of my Contenders that an oversize hinge-pin has helped accuracy greatly.  It probably isn't an issue, but you can always try it.
12. If you don't have a sling swivel stud on any T/C forend, put one on so you can use a Harris BiPod (the 6-9" BR model works well).  Get off the bags and onto a BiPod at the range with a hangar bar-mounted forend (ideally glass-bedded too!), use a good, bunny-eared bag on the buttstock along with these other tips and I believe you'll see a different gun the next time you shoot it.

I hope this information is helpful.

Good and safe shooting to you!  

Javelina

[norm]

I recently picked up a BB 17AH. I couldnt find a lot of info on the round so I got hold of Fred at BB. He was a wealth of information on how to get this round and barrel to shoot. I havnt had the chance to try anything yet. But I am sure Fred could help you out. good luck. norm