Home Forums Reloading Big Game Rifles Kimber Montana 280AI... 140TTSX?

I've been running a Kimber Montana 280AI with Z6 2-12BT, using Nosler Brass, 62g of R22, Fed215, OAL 3.325 for 3190fps... shoots great, but getting stuck cases, shaving the back of the cases and flattening primers on a semi regular basis in the field, but almost never at the range? I'm thinking I must be right on the edge of be too hot in the right/wrong weather/atmospheric conditions? Dropping back even half a grain blows groups right out to not good enough...
Looking at trying different powders after reading (and seeing my changing results) from the temp issues etc with R22...
Not wanting to change projectile as I use this rifle from Fallow to Sambar in Australia, plus Chamios and Tahr in NewZealand at ranges of 10m to 600m and like the way the pills preforms...
I have tried ADI AR2209 and R19... both grouped poorly and way down on velocities for my likings. Just picked up a few tins of ADI AR2213sc to try?
Anyone using the same-ish set up? Load data for a starting point? Ideas even?

Thanks in advance
Ben

Ben,

Book max is 60.5 gr at 3035 with a 160 in the Nosler #6 manual. 3190 is 7STW territory with only one load being faster than yours at 3229. I'd back down a scosh.

Sorry, running a 140g TTSX which has a top of 64g R22 for 3265fps in the latest Nosler book. Each gun being different and the higher pressure from the Barnes is getting me up there quicker I think?

Nosler book has some serious pie in the sky numbers.

Sorry Swado, for some reason I was thinking you said 162 grain bullets.

All good mate... every idea can led to an answer!

In general, or for 280AI specifically?

Ben, have you tried H4831? It would likely reduce the pressure variation that results from temperature difference compared to RL22. RL23 may be the solution, when it becomes available. I know I am want to give it a go in my 280AI.

For reference, I'm running 62.0 grains of RL22 under a 140 grain ballistic tip and getting 3150 fps. I went up to 64.0 @ 3200+ with no pressure signs. Based on your velocity with the Barnes bullet, I'd guess that charge is a little too warm in your rifle.

AR2213sc is the ADI equivalent. I'll give that go and see what happens... cheers

Using Nosler data for a Barnes bullet ? For a standard .280 Rem the Barnes manual max for a 140gn pill is 57gns of RL22.

Flat primers, brass flow into the ejector hole and stiff bolt lift means your loads too hot, its that simple. If it was me, I'd reduced the load by 3gns.

270 WSM: 150 NPT, COAL 2.850, RL-19, WLRP, 60.5 MAX = 3007fps

Kimber Montana:

150 NPT kisses the lands at 2.820 (went 2.800), RL-19, WLRP, 61.0 = 2,839fps

I don't doubt the chrono since my 223 comeups were on the money, but I'm sure there's a little discrepancy.

As a starting point... yes sure why not? I saw that in the Barnes manual too and started at the 280Rem Max of 57g. Not much 280AI data out there that I could find. From there I worked my way up and found that it did not shoot well until I hit the top and tried to get away with it, but it is clearly too hot, which is what I am now sure of... I thought I had already explained that? Sorry my bad.
So my question is any ideas where to from here and/or experiences with the same rifle and bullet combo?

Try a different powder and don't get hung up on RL22. Some people arouned here preach it as the holy grail of powder, but that couldn't be further from the truth.

Try a standard primer. Dont really need a mag.

I shoot 65.0 RL22 in my Cooper with the 140 ttsx. 64.0 with the 145 LRX. CCI 200 primers. Never had a temp issue but I don't use it in hot weather. Works great 15-60 degrees. Covers 99% of my hunting weather

I shoot a .284 Win with the same bullet and get excellent results with R17, the only powder I've tried thus far due to it's great performance. Whether it will perform as well in a taller, slimmer case is the question.

While it has been reported to be a little less temp resistant than some other R powders, among others, it performed perfectly for me at -20 F.

I have spent many days at the bench and range trying to find the sweet spot in this very same rifle. As for the 140 vld I had the best luck shooting 4831 and MRP powder with a mag primer. I even tried standard rifle primers, but I preferred the results and added velocity with the mags.

Using the MRP powder and 140's I had the best overall velocity and accuracy, but what I settled on was the 168 vld and IMR4831 as this was hands down the most accurate load with this rifle. Velocity was just a shade under 2800' but was an absolute hammer out to 600 yds verifying that load.

Clean out your barrel with a cleaning compound on a patch that's on a brush.

I use J-B's.

I'm running 58 gr IMR 4831 with LRM primers and 140 TSX at about 3050 fps no sticky bolt or pressure signs

Really