Is 180 grains the best the 7mm can do?

[223Rem]

Thought about this for a brief moment and was wondering why I have not seen any factory produced 7mm bullets weighing more than 180 grains. Is there less of a return going beyond that point for the 7mm's BC?

We have 90 grain .224 caliber bullets and no .223 is seating that to mag length. Can't someone come up with a heavier bullet for those who load single or use a short magnum on a long action?

 

[TonyR]

Matrix Ballistics in Canada makes a 190 gr 7mm and Bob Cauterucio here in the US makes a 189 gr 7mm. I haven't tried the Matrix but I know Bob's bullets shoot well.

 

[M700]

Dang, a 7mm 180 is one looooong, high BC bullet as it is... You want more? Dang... ;D

 

[RDavies]

To go any longer will mean 8" twist and faster barrels will be needed. This will cause extra rifle torquing, fouling and bullet blow ups.
Some people shooting the bigger cartridges are already getting bullet blow ups as it is with 8-8.5 twist barrels.

 

[TonyR]

I just got the Second Edition of Bryan Litz's book and he includes BCs for the 7mm 189 Cauterucio along with nearly all of the other big 7mm and 30 cal bullets. The G1 and G7 BCs respectively for the 189 are .360 and .703, better than any other 7mms and better than any 30 cal tested. Stablizes in "Nominal" conditions in a 1:9 twist. The same would be true for Bob's 177 although not by as great a margin. The B338 300gr Hybrid was the only bullet I could find with a better BC than the 189. Bryan has once again produced a great reference for shooters. Just the test results on individual bullets make the book a great investment.

 

[GLC]

Hi Tony

I have been tying to get the 189 to shoot for a long time (3 barrels) I even ordered a 4 groove 8:5 twist but no luck, they are actually 1/2 thou over calibre so maybe this is not helping...
I do recall a post I made some years ago about this?.
If there are any theories out there I would welcome suggestions.
The bullets are very well made, I just need a barrel to shoot them.
Actually has anybody had any success with them?

 

[TonyR]

Hi Gary. I haven't tried them myself but one of my friends shoots them exclusively at 1000 with a 280 Remington. I think his barrel is a 1:9 Kreiger and he doesn't push them very fast. I'll have to get some details from him and post them.
I was equally impressed with the BC of the 177 which is my favorite 7mm bullet. I had thought that the BC was a little less than the Berger 180VLD but it is actually higher and they measure and shoot very consistently. I have found it useful to sort Bob's bullets by diameter as well as all of the usual things, but once sorted they have performed very well.

 

[GLC]

Interesting Tony, I wonder if your friends bullets Mic up to the same as mine from memory mine are mostly 0.2845.
Thanks for the info, if you find put anything more please let me know.

We have a nice long Easter holiday, not back to work till Tuesday, then next week the damn Royal wedding (with another public holiday) time to test some loads and bullets, the 180 hybrids are working extremely well, I shot a maximum with them last weekend 75.12 (we score the bull as 5 as opposed to your 10 ring)
Regards
Gary

 

[maxpower]

I measured my 189s and they are .2846" so they are definitely fatter. They are similar length to the Bergers, so twist shouldnt be an issue. As you say, the diameter could be the cause.
It seems the 189 has reached middle age and the added weight is from the extra girth around the middle, not length, just like most shooters.

 

[GLC]

Middle aged Vld's ha!!!
Looks like we have a similar batch, did you manage to get yours to shoot well Maxpower?

 

[TonyR]

I measured my 189s and they are .2846" so they are definitely fatter. They are similar length to the Bergers, so twist shouldnt be an issue. As you say, the diameter could be the cause.
It seems the 189 has reached middle age and the added weight is from the extra girth around the middle, not length, just like most shooters.

I prefer to use the term "Higher Sectional Density" to describe this condition, at least as it applies to me!

 

[maxpower]

I didnt have much luck getting the 189s to shoot well. I hadnt measured them before this post and was using them in a tighter than average barrel. Now that I have a looser Broughton barrel, I will try them again.
I loaded them to the same velocity as with the 180s, but groups at 600 and 1000 were not very good. Then I had only tried them jammed .015" which my 180 VLDs liked. I will try them again soon with a loose barrel and different jumps.

 

[GLC]

Thanks, I was thinking it may have just been me!
Question: I have a new barrel (the sister to my WFCC winning barrel) it was made consecutively and chambered with the same reamer, this barrel (after 250 rnds) is easy 100fps slower than the first, would you say that is a looser barrel,? (I do not have the tools to measure the bore od accurately.

I plan to test the bullet further at various seating depths in an older barrel to see if this has any affect.

Tony,
I will refer to your description in future, much better than saying I have gained a few pounds!

 

[Heman]

I had bought some of Bob's 189's and 177's to try in my .280. But didn't play with them that much. Only testing I had done was with powder charges and quit playing with them before I got to the seating depth testing. Where have you guys found that they like to be seated the best?

 

[TonyR]

I had bought some of Bob's 189's and 177's to try in my .280. But didn't play with them that much. Only testing I had done was with powder charges and quit playing with them before I got to the seating depth testing. Where have you guys found that they like to be seated the best?

I jam the 177s 0.010-0.015 inches and shoot the same load as the Berger 180VLD. I haven't tested the 189.

 

[lynn]

GLC
Next time you go to order up a new barrel order a looser one.The krieger 6mm barrels come in 0.236 and 0.237 bores for loose/tight fitting bullets and Bartlien or Krieger will do the same thing in 7mm.
Lynn

 

[GLC]

Thanks Lynn

Hi Lynn
I was already on that track, I have spoken to Border Barrels in the UK and have sent a couple of bullets to see what can be done.

I really appreciate your comments if border cannot do this your info helps me Immensley.

Regards
Gary

 

[Travelor]

If you do a little math (and hope I did it correctly) the 7mm 180 gr bullet is proportional to a 195 grain bullet in a 30 caliber cartridge.

The BC on the 180's are so good vs what you can get velocity wise - why would you want more? At 180 I think you have reached to max of BC vs MV in a 284 Win.

Just my thoughts and I know there are other larger capacity 7mm's out there.

George

 

[TonyR]

Hi Tony

I have been tying to get the 189 to shoot for a long time (3 barrels) I even ordered a 4 groove 8:5 twist but no luck, they are actually 1/2 thou over calibre so maybe this is not helping...
I do recall a post I made some years ago about this?.
If there are any theories out there I would welcome suggestions.
The bullets are very well made, I just need a barrel to shoot them.
Actually has anybody had any success with them?

Gary,
I just heard back from my friend. He is actually shooting a Cauterucio 190 which is probably virtually the same bullet. He is using straight 280 Remington and 54.8gr VVN165 in a Kreiger 1:9 31 inches long. His chronograph is probably not very accurate but I think he is getting something like 2800 fps with this setup.

 

[car2go4]

Guys, Kirby Allen's the guy that's got this figured out. he doesn't have a website, but you can find plenty of information on longrangehunting