First loads done, crimp and OAL change ?'s

[Kiss of Death]

So after reading as much here as I could, I loaded my first 450BM rounds. I am loading 275 gr. Barnes TSX over H110 to do some testing to see what my rifle likes. I have the 4 piece Hornady custom dies. I am shooting an AR15. I have loaded one other cartridge prior to this (6.8SPCII) but have no experience with crimping.

After seating they were all measured at 2.26" OAL - I then placed a taper crimp which measured .475 at the mouth/taper. At this OAL this has my crimp above the last groove on the bullet. After I finished, while moving them I dropped one which tumbled off my knee, hit a box and then landed on the floor. I rechecked the OAL and it was now 2.245". I am certain it was 2.260 before it fell. The bullet does not look altered in any way; as a double check it I grabbed a comparator and measured from closer to the ogive and it seemed to confirm the bullet is seated .015" deeper now.

I am not feeling so sure about my taper crimps at this point! Should I go back and put a little more crimp on these? Will the shorter round (OAL 2.45") still be safe to fire? I'd appreciate any thoughts on what I've done so far.

[Hoot]

IMHO, in an AR platform, seat your bullets so that a driving band groove is just barely peeking out past the mouth and then drive the taper crimp down into the groove. The nice sharp edges of the grooves provide a good anchoring point. Of course, I can never find a link to my image showing what I just described. Bottom line, give that taper crimp something to bite down into. The resultant COL will be somewhere in the area of 2.18" That's only 8 thousandths less than 2.26 after all.

Hoot

[Kiss of Death]

IMHO, in an AR platform, seat your bullets so that a driving band groove is just barely peeking out past the mouth and then drive the taper crimp down into the groove. The nice sharp edges of the grooves provide a good anchoring point. Of course, I can never find a link to my image showing what I just described. Bottom line, give that taper crimp something to bite down into. The resultant COL will be somewhere in the area of 2.18" That's only 8 thousandths less than 2.26 after all.

Hoot

Thanks Hoot- I do have your diagram saved in my notes, I wasn't sure what to do once I loaded them to 2.26, they were in past the groove closest to the point of the bullet. Am I missing something?

I also have a Lee FCD for 450BM - should I just use that? Can it be used after the taper crimp was applied?

Here is a photo of the first few.

[PRKL8R]

Kiss ,your loads look good. But they are TSX bullets witch only have two driving bands whereas the XPB 275's have three. The band closest to the point is missing on the TSX. I prefer the XPB for the AR platform as it gives o.al. of 2.178-2.180 when crimped in the last band. I like the TSX for my bolt gun since I can seat those to 2.34 and crimp into that band. Yes you can use your Lee crimper after the taper it may or maynot give you more grip . The taper shoukd be ok.

[Kiss of Death]

Kiss ,your loads look good. But they are TSX bullets witch only have two driving bands whereas the XPB 275's have three. The band closest to the point is missing on the TSX. I prefer the XPB for the AR platform as it gives o.al. of 2.178-2.180 when crimped in the last band. I like the TSX for my bolt gun since I can seat those to 2.34 and crimp into that band. Yes you can use your Lee crimper after the taper it may or maynot give you more grip . The taper shoukd be ok.

You know, I looked for those (XPB), it seems Barnes only lists the TSX as the 450 Bushmaster bullet on their website. I pulled their page up, looks like the XPB bullet is listed for the 460 SW, which is how I missed it. I am assuming the load data with the XPB would be the same as for the TSX?

[PRKL8R]

Same bullet ,just an extra groove.

[Al in Mi]

What's the case ID after sizing and after expanding?

Might try skipping the expander, light chamfered the case mouth for more tension.

I don't see any reason the Lee crimp die won't work with those TSX bullets.

[Kiss of Death]

What's the case ID after sizing and after expanding?

Might try skipping the expander, light chamfered the case mouth for more tension.

I don't see any reason the Lee crimp die won't work with those TSX bullets.

Sorry, I forgot to mention I did skip the expander and used a light VLD chamfer - I don't recall the ID measurement, I checked it against what others have posted here it it looked good.

[Bmt85]

Loading the TSX to mag length is going to really affect the crimp. They are pretty hard bullets, and trying to get a crimp into the bullet probably won't work too well. As is already pointed out either run the 275 XPB and crimp in the driving band, or run the TSX out longer (2.33-2.34") to crimp into the band. You will have to window the front of the mag, which is easy enough, but you will have to run more powder for a start load. Starting loads should be near listed max load data from Hodgdon, IIRC. With that said, the TSX has a minimum expansion velocity of 1200 fps, so you don't have to push it to get good performance from it. The 275 XPB has a minimum of 1400fps, so even if you go that route, and don't push it, you can still get good performance.

IMHO, running the TSX out long is the best option for the 450B in an AR, overall. However, depending on what you're trying to do, you might not need the 275 TSX. You can go other routes, and still be effective.

[Kiss of Death]

Loading the TSX to mag length is going to really affect the crimp. They are pretty hard bullets, and trying to get a crimp into the bullet probably won't work too well. As is already pointed out either run the 275 XPB and crimp in the driving band, or run the TSX out longer (2.33-2.34") to crimp into the band. You will have to window the front of the mag, which is easy enough, but you will have to run more powder for a start load. Starting loads should be near listed max load data from Hodgdon, IIRC. With that said, the TSX has a minimum expansion velocity of 1200 fps, so you don't have to push it to get good performance from it. The 275 XPB has a minimum of 1400fps, so even if you go that route, and don't push it, you can still get good performance.

IMHO, running the TSX out long is the best option for the 450B in an AR, overall. However, depending on what you're trying to do, you might not need the 275 TSX. You can go other routes, and still be effective.

Thanks for the input- I am using this rifle for deer hunting in MI woods, most shots are 100 yds or less. I have had good luck with Barnes bullets in other calibers (6.8 SPC, blackpowder) and read a lot of recommendations here on the 275 TSX or XPB as a good choice in 450BM for my use. I have a few boxes of TSX on hand, couple boxes of XPB on the way.