I've been working with a 6mm 105grain Speer bullet. Bullet leaves keyhole in target more often than not. .243 vls. 1 in 9 rifle twist.
Is it possible to stabilise this bullet?
What effect would a sideways impacting bullet have on deer size beast?

It's been my experience that any bullet that keyhole's also has an incredibly tuff time shooting minute of deer!

assuming 100 yards, it means either your barrel is over sized (did it shoot before) or that your bullets are undersized.
jeffe

My 6mm Rem VLS shoots the 105 gr Bergers and the 107 gr Sierras very good. I believe the twist rates are the same. You might try a little faster or slower velocity load. Mine seems to shoot the slower loads better.

Sierra recommends at least 8" twist or faster for thier 107gr 6mm bullet, Berger Bullets also recommends an 8" twist for thier 105gr. Don't know about Speer, but all the 1000 yd benchrest shooters I know of that shoot the 100+ gr 6mm match bullets all use 8" twist. I don't think your bullets are stable in flight.

Velocity does have some effect on bullet stability, but not enough to solve this problem, IF the instability is due to a too-slow rate of twist. I have a 6mm/.284 that has a 1/10" twist Douglas barrel, and it is perfectly satisfactory with the 195 Speer Spitzers (flat based, though). How long are these bullets?

With the 105 Speer Spitzers that is!!

I sort of liked the idea of those 195 grain 6mm bullets!

Seriously - the Speer 105 shoots fine from my factory barrel Rem 700 in 6mm Rem. It's about as accurate as any of the 100 grain bullets I've tried. Best deer bullet accuracy for that rifle has been Nosler's 95 grain ballistic tip, about .6" groups. The 105 Speers were good for a bit under an inch.

I used the 105 Speers for a lot of years using 39.5 grains of 4350 in a 1970s Browning Safari grade. I used this 39.5 grains of IMR 4350 in several rifles and seemed to work nicely in all of them.
The 105 round nose was the most accurate of all, would put five shots under a nickle at a 100 yards every day all the time. Once dropped 6 deer in one afternoon for a farmer using this bullet. The deer were eating him out of house and home in the corn fields and he got a permit to crop them.
I'd suggest giving the barrel a good cleaning with copper removing bore solvent and see what happens.

Jim

I have had keyhole groups on paper targets that were from a fouled out barrel...big suprise to me at that time. I now recognise barrels foul at different rates of use.

I can testify to the fact that with my rifle I was not able to hit varmint size targets a even 100 yards in the field with tumbing bullets fired from M700 in 223.

Now that the barrel is broken in and I keep it clean I am able to hit a penny at 100 yards most shots.

David i believe these bullets are stable in my rifle. I'm still working up loads but heres a couple of 5 shotters in windy conditions.Groups aren't much different at 200 yds.

Thanks for the feedback. What the bullet does is upset AFTER impact.
I range test by pinning target on 25mm ply, the bullet then passes through a 4 foot round haybale then another ply board before burying in soil bank. I often retrieve bullets on the ground between the second ply and backstop.
These 105 grainers often keyhole the second ply board, they are the only bullets that I notice doing so.
They are 1/1.5 moa. They are no longer than 95 b.tip.

I tried shooting 117 grain VLDs in my 6mm-284, can not stabilize them and they leave big keyholes in the targets. The rifle was a .243 Winchester before rechambering, not sure what twist it has. The reason for bringing this up is to suggest that more velocity may not do the trick ( although it may be worth trying ).

I use 85-grain Nosler Partitions or 85-grain Barns XLCs for hunting. The 95-grain Nosler would probably work but I have not tried them.

Tom

Whoops, did not notice the second post. After the first impact, all bets are off. If it's entering the first target head-on, that's as much as you can expect. Perhaps there is something about the first impace that knocks it off kilter, not sure if you should expect a similar effect on game.

You mention that you recover bullets on the ground between the bale and the second sheet of ply. This suggests to me that their is space between the two.

Your bullets will not display this tendency in an animal because of yaw stabilisation. This in plain speak means that the unexpanded shank of the bullet acts as a rudder and tends to prevent the bullet veering off greatly.

Yaw stabilisation does not work in air. Your asymetricaly expanded bullet enters air and starts to tumble.

Air is such a different medium to flesh and bone that any thoughts on why this should happen is not going to have any effect on hunting other than the ability of bullets to 'bust' brush which is a dubious concept.

It is NOT AT ALL UNUSUAL for a long, pointed bullet to kick sideways after it hits something!! IF your bullet makes a round hole on the first board it hits, that is all you can expect!! It will perform differently on game, but may dive off-course in a deer, too! If you want a straight wound channel, you will have to go to a shorter bullet. Try the Nosler Partiton 95-grain!!