30-30 Velocity Oddities

[Idaho-Lefty]

I tried hard to make the FTX bullet work in my 336. I ended up 150gr RN interlock over 748. Very satisfied with accuracy and FPS.
Todd

I had a Pound of, IMR 3031 that, I wanted to, "Shoot UP" before trying, 37 to 38 grains of Win 748 with the 150's.
I Found a Load, Easily ( 2nd attempt ) Tried 31.3 gr's ( just Ok ) and 31.7 gr's of, 3031 ( 31.7 was, "the Magic" ) with Starline Brass, F-210's, Light Crimp, in groove of, the Sierra #2000, 150 grain, Bullet from my, New to Me Used, 20" carbine, 30-A Marlin, Micro-Groove, 1-12 twist, Barrel. ( Est Velocity, 2,235 to 2,245 FPS ).
IMR 3031 was One of the Original Powders that, was found to Shoot "Well", in a .30-30 with GOOD, Case Fill.
Damn, these Levers are Fun to, Shoot at, the closer Range, Steel Plates from,. Field Positions !
Hopefully, I will get to Use it, in N. Idaho for Whitetails, in the Timber, too !
Heard / Read that, Leverevolution Powder, WAS, just about, THE only One to, Use with, the 160 gr. FTX Bullet.

 

[gpoldblue]

See the bottom of the post for my full setup. My question starts from reloading my 30-30 to a cheap plinking load. I started a ladder 5 shots each with 0.5 grain increments from 28 grains of powder to 29.6. I recorded the velocities but focused on groupings. The Targets indicated that between 28.5 and 29.0 was the sweet spot. Then looking closely at the velocities I was confused.

They were all plus minus 20fps of 2060 and showing a decrease in velocity. Huh? Ok velocity doesn't matter holes matter.

Next I loaded up 5 shots each increasing 0.1 grains between 28.5 and 29.0. Shot over same chrono similar weather conditions. Sweet spot was 28.7 grains resulting in a 1.25" group at 100y, which exceeds my expectations. Looked at the velocities again ran some calcs with excel and made a chart and just got confused. The chart below is at least 5 shot averages with 10 shot averages between 28.5 and 29.0. SDs bounce but are around 10fps

View attachment 1530424

Can any one explain this? Every other load I've developed has had velocity increase as powder charge increases. I researched on this site the last few hours to see if i could find an answer and every velocity chart shows a nice regular expected increase. Some thing is happening because 5 shot groups went from 4-5" at 100y down to 1.25". So despite the velocity staying effectively flat accuracy is being impacted. Ultimately there is no problem I just can't stop thinking about WHY!?

Setup:

Marlin 336BL Chambered in 30-30 win 18" barrel. Don't know twist rate.
Nosler 30-30 Brass (only thing available at the time) trimmed to 2.037 per Mitutoyo calipers. New 2022
Hodgon H335 Powder all from same jug (only thing available at time) New 2022
Hornday 160 grain FTX new 2022
Remington 9 1/2 primers new 2022
Seated to cannelure on bullet and taper crimped per RCBS instructions. Crimp measured around 0.002" per caliper OAL ~2.55
Chrony Chronograph, not sure which model. It's not the chronograph it's worked for other loads shot at the same time. Chronograph was about 7 feet ahead of muzzle.
RCBS Press
RCBS Dies <200 loads
Hornday Digital Scale My scale takes about 5 min to warm up but holds accurate after warmup. Provides accurate charges for many other loads.
RCBS trickler
L.E. Willson Trimmer

If I were you,I'd move the chronograph so the 1st screen was at least 10ft away. I recently ran into a situation where groups were good but chronograph showed erratic ES/SD. I moved chronograph further and cured the erratic ES/SD's....I surmised.muzzle blast was the cause. H335 sometimes has alot of muzzle blast especially with short barrels. Just a thought and worth a try.
Good luck and stay safe.

 

[PhilC]

See the bottom of the post for my full setup. My question starts from reloading my 30-30 to a cheap plinking load.

If plinking is your goal nix the jacketed exercise and find some quality cast bullets. You don't need 2000+fps for plinking. With the microgroove barrel you will need a cast bullet finish sized no less than .310".

This is the exact same bullet I cast for my 30-30 that shot the target below. You could also try the LBT 160gr from the same source. Unique might be hard to find, as would other popular ones like Red and Green Dot, but Accurate 5744, either IMR or Hodgdon 4198 & 4895 should be easier to find. I do highly recommend a gas checked bullet vs plain base for your microgroove barrel.

Target below is from my late 80s Winchester 94AE 30-30, Starline brass, 150gr cast flat nose (RCBS 30-150FN), 14.5gr Unique, 5 shot avg velocity 1515fps @ 100yds. I actually shoot this rifle and load in cast bullet competition once a year.

 

[KMart]

I would leave the Chrony at home and use the Garmin. I used one for years and saw all kinds of weirdness with low sun, high sun cloud cover moving in and out, shadows, etc. Plus, the Garmin will most likely NOT drop shots. Or, pick up muzzle blast from another bench.

 

[Chestnut]

Just a thought and worth a try.
Good luck and stay safe.

I would leave the Chrony at home and use the Garmin.

I was borrowing the Chrony, shortly after that post the owner asked for it back so I bought a Garmin. This Garmin chronograph is an amazing device.

Unique might be hard to find, as would other popular ones like Red and Green Dot, but Accurate 5744, either IMR or Hodgdon 4198 & 4895

I can't find H4895 I've heard it works great with the marlin 336s from a few sources. It's no where around me. On your pistol track, i bought a handful of boxes of sub-x bullets for around that $40/box and am going to try a subsonic titegroup load. Crucify me if you like but the barrel is threaded and suppressor fitted.

I'll reiterate that this isn't a problem per-se it's just something odd that I observed. The gun shoots other loads and other powders to groups that far exceed my expectations for a lever gun. Even the load in question is 1.5" groups @100y.

 

[Chestnut]

Had some fun at the range with the suppressor and a bunch of subsonic loads. I learned that my marlin really likes slower speed or is just more forgiving at the lower end? Or maybe it just shoots better with a complete powder burn. Worst group was 3.0 MOA and best was 1.2 MOA. Some of the groups got unfairly large due to shooter excitement and should be ignored notably 7.1 and 7.3.

Target below is from my late 80s Winchester 94AE 30-30, Starline brass, 150gr cast flat nose (RCBS 30-150FN), 14.5gr Unique, 5 shot avg velocity 1515fps @ 100yds. I actually shoot this rifle and load in cast bullet competition once a year.

Load for the target below was 175 grain bullet with 7.1-7.6 gr of titegroup. Velocities were 1050 for 7.1gr and 1090 for 7.6 all the other were pretty linear in between.

I'm going to play around with loads between 7.5 and 7.7 grains. Just have to be careful of the sound barrier. If those don't work out 7.2 grains looks promising.