Barnes 290 tez keyholeing. “Maybe”

[ingramjets]

So I went out and bought a couple 24 pks of Barnes 290 gun tez. After a lot of research on this forum I find these to be a good hunting bullet. I’m using 88 grains by weight of bh209 lot 39. This should be equivalent to 110 by volume of this lot. These load pretty stiff in my knight mountaineer but not excessive. I decided to get quite and bought some harvester black crush sabots. These load a little easier. Today I had time to go out and shoot 3 round’s quick because I was anxious to try them. Range was 80 yards. 2 shots nice holes and the 3rd went in sideways. This was in a piece of pressboard not paper. When I can I’m going to try them with the supplied blue sabots. Would the looser fit cause this or is there another issue I should address. My load should be plenty fast enough. Thanks in advance for your thoughts

 

[MrTom]

With BH you need a very snug fitting sabot/bullet. That keyhole number could well be due to insufficient pressure on the powder column.

 

[ingramjets]

My current load is harvester white lightning 300 grn. Those load tight and shoot well

 

[Pymahunter1]

I believe Barnes warns that occasionally 1:28 won’t stabilize their 290 or 300 grain bullets in 50 cal.

 

[MrTom]

My current load is harvester white lightning 300 grn. Those load tight and shoot well

But you said your keyhole came with the black crush rib 290 grain TEZ Barnes. My reply was based on the black crush rib.

I think I'd be weighing ten volume charges at 110 grains and averaging out the total weight of the ten. While blackhorn can vary in the weight/volume scheme of things from lot to lot, 88 weighed grains is quite a bit off from the recommended 120 volumetric max or 84 grains by weight. Something doesn't add up in my mind..

 

[Ninering62]

So I went out and bought a couple 24 pks of Barnes 290 gun tez. After a lot of research on this forum I find these to be a good hunting bullet. I’m using 88 grains by weight of bh209 lot 39. This should be equivalent to 110 by volume of this lot. These load pretty stiff in my knight mountaineer but not excessive. I decided to get quite and bought some harvester black crush sabots. These load a little easier. Today I had time to go out and shoot 3 round’s quick because I was anxious to try them. Range was 80 yards. 2 shots nice holes and the 3rd went in sideways. This was in a piece of pressboard not paper. When I can I’m going to try them with the supplied blue sabots. Would the looser fit cause this or is there another issue I should address. My load should be plenty fast enough. Thanks in advance for your thoughts

88g W BH209 is not 110g V. Its 125g -ish +/- by volume.

 

[ingramjets]

i was just adding that i have been shooting the whitelightning with the green sabots and they load tight and shoot well the 88 grains by weight should be the right conversion of lot 39. as i have confirmed and others have as well. it changes lot to lot unless im missunderstanding something

 

[bronko220002]

Unless your accuracy is superb, why would you want to punish yourself shooting that much bh209? I've found that my accuracy deteriorates above 75 gr bh209 (wt).

 

[BuckDoeHunter]

Possibly, you drilled the sabot. What was the temp outside? Not enough cooling time between shots? The crush rib sabots were too loose for me when I used them with the TEZs, that was in a CVA Apex.

 

[ingramjets]

temp was around 35 degrees, i tried to find the spent sabots but couldnt find any. had plenty of time between shots. the supplied sabots do load harder so i will try those next trip out

 

[brad502a]

The powder charge by weight could be correct per the lot #, not an issue. The twist rate issue is with the Barnes 300 Expander which is a long bullet, not the 290 TEZ. I would definitely try the blue sabot. How easy to load is easy? I alway had best accuracy with about 100 to 110 grV BH209 but different rifles like different things. YMMV.

 

[ingramjets]

The powder charge by weight could be correct per the lot #, not an issue. The twist rate issue is with the Barnes 300 Expander which is a long bullet, not the 290 TEZ. I would definitely try the blue sabot. How easy to load is easy? I alway had best accuracy with about 100 to 110 grV BH209 but different rifles like different things. YMMV.

i could seat the load with just using my hands on the ram rod i didnt need to push from the top. with the supplied sabots the blue ones i have to put my bullet starter on top of rod to push it down

 

[brad502a]

That seems a little too easy, especially in the cooler weather.

 

[ingramjets]

That seems a little too easy, especially in the cooler weather.

I tend to agree. I will give them a try with the supplied blue sabot

 

[The long rider]

I agree, those crush rib sabots are too loose causing the bullet to strip the rifling (not engaging) and causing the keyholing. You need a tight fit with any muzzleloader, whether it's a smokeless, inline or a sidelock.
I also agree with Ninering62 88gr. of powder by weight is more than 110 gr. of powder by volume, unless the powder has a shitload of humidity or solvents. I shoot 100 gr. measured out with a volume measure, then pour that powder in my digital scale and see what it reads, then weigh out as many of the charges I need with the scale.
I just shot the same TEZ bullet last week using the supplied blue sabot in my Lyman Signature series with a 1-24 twist rate and they were all over the target @ 100 yds. After walking back and forth to the target I found the blue sabots with most of the pedals torn off but not blown, I changed to MMP black sabots and the groups got better. The Barnes bullets/sabots are about 8 years old and been in my unheated garage. I'm thinking the plastic had gotten hard with age and temperature variation.
Anyway, drop the crush ribs and your charge and your problems should go away.

 

[billyboy*]

Not sure if it was mentioned above. You might try knurling. I also anneal the Barnes Untipped bullets like the .40 Cal 195 Gr MZ & 275 Gr XPB. Tighter fit is what you want.
.

 

[ronlaughlin]

There happened to be one bottle of Blackhorn lot 39 in the house. 100g out of this bottle weighs 76 grain. This bottle was unopened until this morning.

So extrapolating, it then is realized that 110g of Blackhorn lot 39 will weigh 84 grain.


Keep in mind this is just one measurement done by one person using one set of tools available in this house.

 

[ENCORE50A]

Tapped FULL volume.

 

[brad502a]

Seems like everyone is concerned about the powder charge, that it is too hot. It is NOT the culprit, IMHO. Thank you Encore, the data is much appreciated.

 

[phalanx]

Just for reference (confusion) last Aug ingramjets posted the below topic

Thread 'bh209 lot 39' bh209 lot 39

Consensus back then was his weight was correct