.375 ruger, RL15, Barnes 270 gr TSX loads from today

[tammons]

.375 ruger, RL15, Barnes 270 gr TSX loads from today

Gun is a Savage control feed long action, duromax bedded stock, SSS trigger, 22" barrel, EGW base, burris extreme rings, Leupold 2-7x scope.

75d F

At 2600 fps over IMR4350 shoots about 3/4".

This was a session looking for a max in my rifle.

71 - 2693
72 -
73 -
73.5 2721 (seems low in comparison to 71)
74 - 2704 (bad ??)
74.5 - 2640 (bad ??) semi hard bolt lift
75 - bolt lift okay
75.5 - Very hard bolt lift, ejector mark on brass

I will be doing more chrono testing around 74 gr in a week or two if anybody is interested.

[marshall]

Tammons,

It sounds like you have quite a nice custom rifle.

It just so happens I was at the range today with several samples of Ruger .375 and Barnes TSX's over RL-15.

A few weeks ago I loaded up some Barnes with 4007ssc per the Barnes manual. They shot very good but they were a little slow. The chronograph confirmed their max was indeed the max in my rifle too.

http://forums.outdoorsdirectory.com/...ad.php?t=47112

I felt that the velocity was much slower than the potential of the bullet weight and the Ruger .375 cartridge so I set out today with (4) of each sample as follows:

RL-15
Brass trim 2.571
CCI 250
Barnes TSX 270gr
COL 3.313

72.9gr 2661 avg
73.2gr 2687 avg, 26fps increase
73.5gr 2712 avg, 25fps increase, Barnes published max charge???
73.8gr 2739 avg, 27fps increase, nice group
74.1gr 2762 avg, 23fps increase, nice group
74.4gr 2787 avg, 25fps increase
74.7gr 2803 avg, 16fps increase, primer showing pressure, a little drag on bolt lift, case head measured OK.


I went home and gave the rifle a thorough cleaning and loaded up (6) samples at 74.0gr and went back to the range. After a fouling shot I fired five consecutive shots in 15 minutes from a fore-end rest and butt bag. They grouped center to center at .488", these are to date the best loads for my rifle. They are a little slower than expected but as accurate as I could ever hope for and well below max pressure evidence in my rifle.

Final load:
74.0gr RL-15
Brass 2.571
CCI 250
COL 3.313
2756fps

Your results (may/will) differ, my rifle is a production Ruger .375 Alaskan with a 20" barrel and a mushy stock with a Vais muzzle break and a Timney trigger set at 3 pounds.

http://www.muzzlebrakes.com/index.htm

http://www.timneytriggers.com/sunsho...7-MKII-24.html

[tammons]

Thanks for the post. I have been waiting for somebody to do this so I could check my numbers.

My rifle is nothing special. I had been shooting a 338/284 wildcat when a new 375 ruger barrel came up for sale on the savage forum for a decent price so I could not pass it up.

I am into the whole barrel swap thing with savages, so I have several actions. They are easy to work on, and you can swap out a barrel in about 10 minutes.

I picked up most everything used. Got the CF action used on that same site. Its an older SS action, but hey it works. Added a SSS trigger I already had and a Heavy duty recoil lug. Also got a used duromax stock on the same site, for about half price. Bought a new EGW base, already had the rings and scope. Barely snagged 100 rounds of 375 ruger 1x for $22. Which I could find some more of that.

Funny, our chrono readings at 73.5 gr are 9 fps different and it seems like we are close as far as max loads. We are using the same primers, same powder.

I ran it through quickload again, at your shorter COL. The cartridge seems to have an efficiency advantage in real life and adding 1.75" to the barrel length in QL comes close to what we are actually getting in fps.

If I take your 73.5gr load, run it through QL adjusted for efficiency as above I get 2712 fps. If I apply that to my longer COL and longer barrel I get 2728 for my load which is real close to my actual of 2721 fps.

With RL15 I am showing a 100% burn, which to me sez a slightly slower powder might give a bit more umph. I also shoot a 7mm-08 and have been getting some impressive numbers with RL15 and the 162 gr amax, but RL17 should give me another 50 fps or so with that cartridge, so I might pick some up soon.

For my barrel length.
If I run QL again with RL15 I get 73.5 max and 2730 at 63.8k 100% burn
If I run QL with RL17 I get 73.5 max and 2780 at 63.8k 100% burn
(I really think you could get about 2825-2850 since QL reads high overpresure with bullets set deep into the case)

That said, I think you could be getting by with .5 gr more powder by more bullet jump or maybe the temp, so I might try your 3.313 COL or thereabouts.

One thing thats been bugging me though is my chrono and I was convinced it was been reading low. Looks like its close enough though.

BTW - What was the temp and what chrono do you use ??

[marshall]

Tammons:

I have a Chrony Master Alpha, it seems to do a fine good. There are other models out there that have more options but this one does what I need it to.

It was 49 yesterday morning when I started, it reached 78 by mid day when I went back for round two. Humidity was 45%, barro pressure was 29.95 and elevation is 1750. Most of that makes a very small difference but I record it just for reference. We typically have about 30 degrees of temp swing here everyday regardless of time of year.

I currently don't have that fancy computer program to evaluate powders prior to reaching the range. I go with published data, start low and go up to find the best results for my application.

After reading several comments from posters here and other places about techniques and errors I have developed the following procedure that works well for me.

I load (4) of each sample and start with a lower charge than I anticipate as a final product. This low charge becomes the sighting and fouling round at the start of a run, no other scope adjustments are made for the remainder of the shots.

I use incremental charge increases of .3gr and load past published max loads because I will evaluate each case and the chrony results after each shot before going the the next. I measure the case stretch which is very minimal but it grows .002 - .003 from low to high loads. I also measure each charge twice to improve the accuracy of the data collected.

I don't full length resize anymore with my rifle. I have the dies set up to push the shoulder back just far enough to safely chamber the round. This reduces the working action of the brass and extends case life. When I used to full length size the brass on this round it moved the shoulder back .017 and then it would stretch back to the chamber length when fired reducing the brass life.

With the small steps in powder increases you easily see that the velocity steps up nearly linearly. Once the velocity begins to drop off for a given increase in charge I know that I'm getting close to the max load for the combination in question. Sometimes the primer or case will show bad signs first.

Using this technique I have seen a pattern. Two samples will usually group better than the rest and they will be right next to each other, in this case sample #4 and #5 grouped well. I will then load with a charge in between the two allowing for a weight accuracy of +/- .1gr, this will still give me a charge in between the two that did a good job. If I'm not totally satisfied with the group I will vary the seating depth to see if things improve. This method uses up a lot of bullets but it has netted some really good results with my rifle.

I chose 3.313 COL for this load because of the position where the first groove in the TSX was in relation to the case trim length. I use a light tapper crimp, too much and the shoulder will bulge with this step. It just so happened that this combination worked very well and seating depth wasn't messed with. The bullet jump / throat length with this COL is high but worked well. The bullet is measured to be .124 off the lands in my rifle.

One more thing that I have started doing while collecting data is:

If there are 10 samples I use ten targets. I put sample #1 in target #1 and #2 in target #2 and so on. I only shoot one shot of each sample in each target. Then I clean and start over with the same procedure until I have shot all (4) samples into each target. This procedure allows each shot to be a true reflection of the previous same number sample. For example, each sample #1 is a cold clean barrel, each #4 is a slightly dirty warm barrel and each final sample is a warmer dirtier sample. That way the bullet impacts the target in a more consistent relationship.

I used to fire all of one sample in one target and move on to the next but the groups weren't a true reflection since the first shot was cold and the last was hot.

Perhaps I'm nuts but these steps have really improved my data collection efforts and a long day at the range is good mental therapy for me anyway.

By the way, I originally said that I wanted more speed. I'm satisfied with these results. If weight is linear, and I'm not sure if it is. My best results with a Sierra Game King 300gr bullet came at 2653fps and Nosler Accubond 260gr bullets came at 2840fps. That's a difference of 62fps per 10gr of bullet weight. That would put the Barnes 270TSX right around 2778fps and my final load of 74.0gr of RL-15 is right in that area at 2756fps.

I'm headed to the range in a few minutes with a friends .375H&H to hone in on a batch were working on. Results of that test on another post within 24 hours.

[marshall]

By the way, primers are like girl friends, everyone has their favorite. I have tested Federal 215, 215M and CCI 250's with several of my previous runs.

In every case the 215's had larger ES and SD numbers. The 215M's did well but they lost velocity when compared to the 215's.

The CCI 250 velocities where right in the same area as the 215's but they had very low ES and SD. Now I only use CCI's and let my buddies use up the Fed's.