I have both a Barnes & Nosler manual. I have some Barnes 120 gr TSSX BT bullets for my 7mm08. I had been using 45 grains of IMR 4350 with this bullet with ok results on grouping at 100 yds. I was interested in seeing what if any difference could be made in the rifle's accuracy by tweaking the powder charge. Barnes doesn't list IMR4350 for this bullet weight. It is the minimum charge listed in the Nosler manual with a 120 grain ballistic tip. I have changed the seating depth of the bullets to where they just fit into the magazine but chamber without touching the lands. I have loaded a few with this new seating depth with the 45.0 grain charge. When I loaded the next few rounds with 45.5 grains I noticed the load seemed to be compressed. I experienced no abnormal pressure signs with the 45 grains and a slightly deeper seating depth with the same bullet. Is there much if any chance I'll be flirting with excessive pressures with this extra half grain of powder? Maybe some of you have a suggested load for this caliber with the Barnes 120 grain bullet and the IMR 4350 powder. BTW this is the only powder I've ever used in my .270, .243 & 7mm08. I was obviously trying to stay with the same powder. Thanks for any suggestions.

Cartridge          : 7 mm-08 Rem.
Bullet             : .284, 120, Barnes 'TTSX'BT 30298
Useable Case Capaci: 47.971 grain H2O = 3.115 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : IMR 4350

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-20.0   82    36.00   2208    1299   26040   6362     77.2    1.434
-18.0   84    36.90   2261    1362   27583   6599     78.6    1.399
-16.0   86    37.80   2315    1428   29223   6836     79.9    1.365
-14.0   88    38.70   2369    1495   30970   7071     81.2    1.332
-12.0   90    39.60   2424    1565   32826   7305     82.5    1.299
-10.0   92    40.50   2479    1638   34812   7537     83.8    1.267
-08.0   94    41.40   2535    1712   36925   7766     85.0    1.236
-06.0   96    42.30   2591    1789   39180   7992     86.2    1.205
-04.0   98    43.20   2647    1867   41588   8213     87.4    1.175
-02.0  100    44.10   2704    1949   44162   8429     88.5    1.146
+00.0  102    45.00   2761    2032   46915   8640     89.6    1.117
+02.0  104    45.90   2819    2117   49863   8844     90.7    1.088
+04.0  106    46.80   2877    2205   53024   9041     91.7    1.060  ! Near Maximum !
+06.0  108    47.70   2935    2295   56417   9231     92.6    1.031  ! Near Maximum !
+08.0  110    48.60   2994    2388   60062   9412     93.5    1.002  !DANGEROUS LOAD-DO NOT USE!
+10.0  113    49.50   3052    2483   63986   9583     94.4    0.974  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba    102    45.00   2923    2276   55653   9020     95.8    1.040  ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba    102    45.00   2570    1760   39065   7933     80.7    1.205
   

A little compression is not normally an issue. You are not close to max pressure per QL

Thanks. Just curious about where you got this load data?

Simply a run from QuickLoad software.

Your exact OAL and capacity would change it slightly.

I think your choice of powder is fine for 140 to 160 gr bullets but a bit slow for the 120 gr.

H4350 is perfect for the 243 & 100 gr bullets. It should be fine for the 270 & 130 gr bullets though the real experts might disagree.

For your 7mm 08 & 120 gr TSX, I would use Varget or similar powder. I have tried VV N150 & Re15 as well.

You need to check your loads on a chronograph. You should get 3050 fps or so according to the Barnes manual.

Thanks for the suggestion.

Just a thought. If you do not mind my asking - how long have you been reloading?

Just to be cautious - I would suggest a couple of things in case you are not aware.

Firstly - pressure goes up exponentially - in other words pressure goes up faster than velocity. Beyond a particular point - you do not get any increase in velocity but pressure keep rising at a faster rate.

You will not have a problem with IMR 4350 & 120 gr TSX as the powder is too bulky to cause pressure problems unless you really force a heavily compressed load. But you could have serious trouble with pressure if you used a faster powder. So please take note!

Secondly - always remember that the monometal bullets like TSX etc will cause pressure spike if seated too close to the lands of the rifle. Barnes recommends a minimum 0.050 inch seating away from the lands for these bullets. The copper bullet is harder than normal lead core bullets and so it does not squeeze through as quickly & hence the pressure spike.

Again - a chronograph is critical. Once you know you are near max velocity, you need to stop increasing the powder charge.

Have fun and be safe.

Actually I have been reloading since 1985. I only reloaded .270 Win and .243 Win all of those years and strictly for deer hunting and enjoyment. I never experimented with loads and always kept to the "middle" load listed in my Speer manual. My wife of 36 years got interested in my favorite sport, deer hunting in 2009 and after seeing she was serious added the 7mm08 as her rifle. She's actually a better shot than me having killed two deer this year at over 200 yds. Anyway I have just recently gained an interest in trying to fine tune a load for each of the three deer rifles that we have. I don't own a chronograph. Probably a mere "rookie" at reloading to most of you on this forum, but I enjoy reading the posts and gathering information and I do appreciate your interest in my questions.