Crimping into the cannelure (Barnes TTSX)

Sako308

Well-Known Member
I am loading Barnes TTSX 130gr .270 WSM. I have measured 0.050" off the lands of my rifle as suggested. This puts the tip of the neck in the middle of the first of the three cannelures on the bullet. In the past I have only crimped onto the main body of the various bullets I have used on a .308. I use the Lee factory crimp dies. What technique does one use to crimp into the cannelures on these bullets. The groves are quite wide and deep compared to Hornaday Interlock/SST for example. It feels strange crimping into such a wide groove.
 
Barnes recommend crimping onto the lands - not the grooves. They also recomend a long jump to the lands for best performance. (70 thou springs to mind). So just seat the bullets a bit deeper & re-work up your load to drive the bullets fast for optimum expansion.
Works fine for 308.

Ian
 
Barnes recommend crimping onto the lands - not the grooves. They also recomend a long jump to the lands for best performance. (70 thou springs to mind). So just seat the bullets a bit deeper & re-work up your load to drive the bullets fast for optimum expansion.
Works fine for 308.

Ian

Barnes don't recommend crimping but I have always done so with good results, plus peace of mind when out and about. I see from pictures of Barnes factory ammo they crimp into that first cannelure as well. It's trying to gauge a light crimp into a cannelure that was new to me.


Where do I seat the Triple-Shock, Tipped TSX and LRX bullets?
Answer. We recommend seating these bullets .050″ off the lands {rifling} of your rifle. This length can be determined by using a “Stoney Point Gauge” or other methods. You do not have to seat the bullet at, or on one of the cannelure rings.

Do you recommend crimping your bullets?

We usually don’t recommend crimping our smaller-caliber bullets. However, if you choose to do so, a light crimp is best. Heavy caliber bullets (.375 and up) for large game require a heavy crimp, as do most revolver and lever-rifle loads.





 
I've done a bit of reading, it looks like the best thing to do with the cannelure is just to lightly roll crimp it with the Lee bullet seating die. Will give it a go.
 
Oops! - I stand corrected - humble apologies. - It's strange what the memory can do. I thought I had read it somewhere & had convinced myself!
However I maintain that my method of a light crimp with the neck mouth on the land using a Lee Factory Crimp Die is a good way to ensure best repeatability.

Ian
 
With the 130grain TTSX in 308W the case mouth just misses the land if the case is trimmed to SAAMI 2.005" and the bullet seated to SAAMI Max COAL 2.81"

In the 130grain data Barnes sent to me, they suggest setting the bullet in deeper than SAAMI spec., to 2.785" which happens to bring the case mouth onto the land.

I tried both seating depths, and always used the Lee Factory Crimp die. Crimping onto the land feels more repeatable, and is my current preference.

Alan
 
I would rather crimp onto the land as with my .308 but if I go just past the first groove I'm on the lands on my Winchester 70. If I seat deeper then I would be crimping onto where the bullet starts tapering to the tip, in front of the first groove. When I did this with my .308 in a Sako 85 I couldn't get anywhere near the lands with the 130gr TTSX. The Winchester seems to have a much shorter throat (if that's the word). Doing some loading this morning so will try roll and taper crimping into the first cannelure and see how it goes.
 
I would rather crimp onto the land as with my .308 but if I go just past the first groove I'm on the lands on my Winchester 70. If I seat deeper then I would be crimping onto where the bullet starts tapering to the tip, in front of the first groove. When I did this with my .308 in a Sako 85 I couldn't get anywhere near the lands with the 130gr TTSX. The Winchester seems to have a much shorter throat (if that's the word). Doing some loading this morning so will try roll and taper crimping into the first cannelure and see how it goes.

Terminology check...

In my post I was just referring to the 'land' of the bullet...the full size/bore section measuring Ø 0.308".

When chambered the bullet ogive is well back from the start of the rifling in my barrel.

With the 308 130grain TTSX bullets seated at the 2.785" COAL, one groove remains totally visible outside the case. The case mouth is crimped onto the 0.308" section of the bullet between the first and second grooves.

When seated to the SAAMI depth of 0.281" all of the middle groove was enclosed and the case mouth crimped into it...the case mouth just brushing the shoulder of the land between first and middle groove.

Alan

ps Just re-read the thread, and from your OP I see you are already on the first groove and not the middle one...If it is of any help or consolation...in my limited experience I found no difference or disadvantage consistency-accuracy-wise with crimping into the groove in practice. :)

It did cross my mind that the case mouth was being work hardened more by crimping into the groove and thus would need stress relieving (low temperature annealing) sooner. But maybe the crush against the land of the bullet is hardening the brass about the same as the upsetting action of reducing the diameter into the groove...
 
Last edited:
Thanks for your thoughts, I've possibly been overthinking the whole thing. Loaded up 20 rounds, 5 different charges, so will see how they shoot. Used the Lee factory crimp die into the first cannelure and it was no problem, just over 50 thou to the lands and the same length as the Norma factory ammo I was previously using. Cheers.


image.jpg
 
Back
Top