Ammo for 17.5" Twist

H

hawkeye wizard

New member
Even when it warms up to 65 degrees, shooting EPS through my 17.5" twist, 2-groove barrel, I'm getting yaw (outlines of slightly tipped bullets) at 50 yards. What ammo do you recommend for slow twist barrels??????????????
Thanks
 
I had better luck with faster...1074 rather than mid or slow 1050s through 1060s. In the end, I got fed up because I shoot a few night shoots and you never knew what you would end up with for temps. Made a nice tomato stake.
 
Don,
they're too short for tomato stakes. Next time you take one of those bad ole 2 grooves off send it to me and I'll buy you a 1X4X4 pine stake for it.:)
 
I know at least one guy with one of those barrels that was shooting 1080 stuff and just tearing us up with it. Have you checked your 17.5 to see exactly what the twist is? Some have been pretty suprised.

Charlie
 
It's a 2-groove, reverse taper barrel. Checked with a patch on a cleaning rod, the twist appears to be about 1 / 18. I've been shooting EPS 1008-05123 labeled as 1069. I can't score much over 2000 on an ARA target. My flier 50s exhibit more yaw than the shots that go where I call them. The barrel is clean and none of my other rifles with faster twists exhibit the yaw on the target.
 
When I first got my 2gr 17.5 it was the hottest thing since sliced bread, now it's as old as Mother Hubbard's shoes. Mine keyholes too, shoots a lot of 10's, very few X's, and the 10's are all over clock. Here's what I found out after many agonizing experiments and talking to many benchresters; these barrels are killers if you live/shoot in the desert, like Texas or Arizona, where it's common for temps to be over 100°F. In my part of the country, that ain't gonna happen. Thanks, Douglas
 
I had a barrel just like yours at any tempeture it would keyhole tried many things to try and fix this. The only thing that it would shot was Lapua I finally rebarreled my 40X with a 16 twist Broughton and have had no more problems since and it is shooting great.
 
I have the same 17.5" Twist 2-groove, reverse taper barrel on a Turbo action. My advice is try a little Lapua Center-X and see if that improves things, it did for me.
 
Greatest thing since sliced bread! Just keep some lapua handy for cool weather,they will shoot big scores in cold weather,IF you put the right bullets in.
 
some folks change barrels like they change socks and then report here what killers they are and everyone jumps on the bandwagon. A friend and me laugh about it, the next hot barrel will be Adams & Bennet. Go back a few years when these reverse taper 2gr 17-1/2's were being highly touted. I was a neophyte and gullible enough to jump in with both feet. As a joke on a different thread, I offered up this barrel for sale cheap, surprise, no takers. I doubt the company even makes them anymore. Thanks, Douglas
 
Hawkeye,

I've been hanging around on the rimfire ranges of New England for years as well as making the occasional road trip down to visit my friends in the more southern parts of our country, and from everything I've read, heard, or seen my guess would be that your problem isn't the twist rate, but more the fact that you're trying to shoot a 2-Groove barrel in a cooler climate. I'm not sure if you'll be able to find an ammo of any speed that will be able to satisfy what you're looking for. Like Douglas said, most 2-Grooves seem to only perform well in the warmer climate. By the way, I've shot 6-Groove 16's, 17.5's and 19 twists with great success. In fact, I've got a 17.5 twist tight bore on my little Sako Sporter right now that's second to none.

Good luck with your quest.

Dave Shattuck
 
I will start off by saying I never have owned a 2 grove, but for the life of me I can't figure out what the number of groves would have to do with anything regarding bullet yaw.

Seems to me if the twist rate is exactly the same from a 2 grove to any number of groves, unless the bullet is slipping in the groves the spin of the bullet would be exactly the same from 2 groves to any number of groves.

I would also expect if the bullet was slipping in the rifling, that a retrieved bullet shot into water or other way of preserving the shot round would be pretty obvious.

I know this topic has been beat to death but I remember BC implying he knew exactly what was causing the issue and why the lapua shot but the eley keyholed but that was another one of his thoughts he started but never completed before going on to something else.

It would be interesting for someone to post some close up pictures of a retrieved bullet from a 2 grove that was keyholing. Is it slipping in the rifling?

Charlie
 
Try Eley round nose. My 17.5 twist keyholes with EPS in cold temps, but is fine with the round nose in temps as low as 30.
Steve
 
I was noticing the same with mine from time to time. What I did id go through the hopewell method of tuning until I found the best group. I then put on a Pappas noodle and it came right in. I couldnt get near the groups without the noodle as I could with it.
 
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