180gr rcbs round nose flat point load

[six_gun]

It has been a few years since I have posted so forgive me for showing up and asking stupid questions.
I shoot cowboy rifle silhouette with a 24” marlin 336 with a Ballard rifling. I’ve been using a max load of lvr and a Sierra 170 gr bullet. It has been working really good and I’ve won lots of matches using using this load just on the rams. You all know my problem. I can’t find Sierra bullets any more.
I used to cast lots of bullets but got busy and started using the sierras.
I casted a batch of the above rcbs bullets, gas checked and lubed them. They weigh 190gr.
I loaded some up with 33gr of lvr and they shot really good and would knock the rams down with authority. Trouble is the primers showed a little too much pressure.
The velocity was around 2150fps.
Any suggestions

[Bazoo]

Back off the powder charge a couple grains?

Switch primers to one that's less violent.

Switch powders. W748 and the 30-180-FN did well for me, except the nose was too long for my throat.

Cast of an alloy that's lighter like Lyman 2 or Linotype.

Convert the mould to HP to lighten it.

Try a different lube. NRA 50/50 makes the highest pressure according to Veral Smith. He says his lbt blue is bout the lowest.

Use a different bullet that drops lighter.

[waksupi]

I really don't trust primers as indication of high pressure. The varying thickness of the primers can mislead you.

[wmitty]

If you could knock the rams over with less momentum you could drop your velocity to reduce chamber pressure. I don’t know how jacketed vs cast construction affects ability of bullet to drop a steel ram; sounds like you do. Were the 170 gr sierras going much faster than 2150 fps? Maybe the 190 rcbs boolits could still do the job at 2000 fps and have an acceptable chamber pressure.

[six_gun]

I used this bullet to win my first state championship match way back un 2005, I just don't have the recipe I used. The Sierra 170 grain with 36 grains of LVR is going about 2350 fps with a SD of 15. It also shoots really flat with a 4" deviation out to 200 yards. With a scope on a bench the load is consistently around a 2" group at 200 yards. When I tested the rcbs bullets with 33 gr of LVR I didn't use my chronograph because at this northern latitude it doesn't work in the winter months, but it shot good from a bench with my Williams aperture site.

The rams weigh about 40 lbs and if they are hard set I have rang rams with my 38-55 when I get a center hit. I think the solution will be to go try some loads with a little less powder and see what works.

I have found that it isn't necessarily the velocity that causes problems with cast bullets but pressure is the biggest problem. The Hogdon LVR powder gives really good velocity with low pressures and my rifle really likes it. There used to be good load data available for the rcbs 180 gr bullets but the power companies only want to give data for up to 170 gr bullets now days and there are lots of good powders that we need data for heavier bullets in the 30-30. Same goes for heavy bullets in the 38 special, but that is another rant.

I have a good friend that has a company that loads ammo for the military and he has a pressure gun but not a 30-30 barrel. Maybe I'll have to break down and find him a 30-30 barrel that he can adapt to his pressure gun and do some load development of my own.

[Maineboy]

If you can find an RCBS cast bullet manual number one (and only) edition you can find some data for that big boolit. I have the same mold and the manual and I've tried a few of their loads never noting any pressure signs. Of course LVR is not included in their tested powders but if you'd like, I can provide you with their data. Their test firearm had an 20 inch barrel and none of their loads exceeded 2000 fps.

[Larry Gibson]

I really don't trust primers as indication of high pressure. The varying thickness of the primers can mislead you.

Concur, especially if the cases are full length sized.

[charlie b]

Lyman cast bullet handbook shows max of 2180fps for 173gn bullet with CCI primers, 748 and H335 powders. ~33,000cup.

[PAndy]

You can reliably take 200m rams under 1900 fps with that bullet. I actually shot it with 4198 powder out of a 26" winchester 94. in my view, no need to push the high speed unless you want to. mine weighed 197-198 gr with lube and GC

[farmbif]

all the tech stuff above my pay grade but all my 30-30's seem to like 28 grains of 3031 under the heavier cast bullets. not sure if it will knock the rams over but sure will kill most anything it shoots in the boiler room.