270 Sherman Build completed!!!

[Idaho Trecker]

After much debating on which 270 cal cartridge to go with and reading all the great threads on the different Sherman designs I opted to do my first semi-custom in a 270 Sherman and couldnt be happier. Elkaholic (Rich) was very very helpful in answering all the questions that I had throughout the process and facilitated renting his reamer and getting dies to me.

My build is on a Rem 700 long action that was trued and I dropped in a Timney 510. For a barrel I went with a 27" finish Lilja 1:8 twist 3 groove #5 contour. I opted to use the factory stock that came with the rifle since it is in such good condition and I am partial to nice walnut stocks. I topped it with a Talley 20 moa base, NF ul rings, NF 5.5-22x56 and vortex level. The rifle weighs in at 11.2 pounds with scope and accessories.



I had all the work done at Diamond T Rifle Shop which was top notch!!

I decided to only shoot 165 Matrix and larger bullets (hopefully the 170 Berger comes to life soon) out of this so I had it throated for them specifically.

I fireformed 100 rounds of winchester brass then went to work breaking the barrel in with my test loads being loosely based off of 280 AI data with 175 bullets. This put me really close for shooting the 165 Matrix.
During breakin I shot a ladder of RL 33 and IMR 7977.

The group on the left side is the ladder of RL33. The center group is IMR 7977.
I hit my max with RL 33 at 64 grains and 60 grains with IMR 7977. The lone shot up top is my one shot with retumbo which was a total fail and has left me puzzled (a question for later).
Unfortunately I do not have a chrono so I cant tell you speeds yet but now to the good stuff... I have a SHOOTER!!!
The tiny group to the right of center is my first 3 shot group at 200 yards with 62.7 grains of RL 33... It measures .320"!!!!!
Next I plan on trying some groups with IMR 7977 and figuring out the Retumbo. Also I may try some HBN and see if it will let me get some more speed and save my throat some.

When I get some more data and speeds I'll add to this post.

Just thought I would share.

 

[FEENIX]

Congrats on a mighty fine build! Looks like you're off to nice start.

I have the same barrel except it's 30" and #7 contour in my .270 AI and mine stays pretty clean.

I didn't have much luck with Retumbo or RL33, so far H4831SC is best with IMR 7828SSC as a close 2nd for the 175. I have the IMR7977 but haven't had a chance to load any yet and perhaps do more testing with 165.

Keep us posted. Cheers!

Ed

 

[Idaho Trecker]

Congrats on a mighty fine build! Looks like you're off to nice start.

I have the same barrel except it's 30" and #7 contour in my .270 AI and mine stays pretty clean.

I didn't have much luck with Retumbo or RL33, so far H4831SC is best with IMR 7828SSC as a close 2nd for the 175. I have the IMR7977 but haven't had a chance to load any yet and perhaps do more testing with 165.

Keep us posted. Cheers!

Ed

With accuracy like I got with the RL 33 I dont know if its worth messing with anything else unless I can match it and get more speed. I PM'd you a few times when I was getting components together for this build in regards to your barrel and speeds which both were very impressive.
The one load of Retumbo I tried punctured the primer and was not good at all!!! Would you be willing to PM me your data with your AI and Retumbo if you tried it with 165 bullets?
Any idea why the primer punctured? Would that be over or under pressure?

 

[FEENIX]

With accuracy like I got with the RL 33 I dont know if its worth messing with anything else unless I can match it and get more speed. I PM'd you a few times when I was getting components together for this build in regards to your barrel and speeds which both were very impressive.
The one load of Retumbo I tried punctured the primer and was not good at all!!! Would you be willing to PM me your data with your AI and Retumbo if you tried it with 165 bullets?
Any idea why the primer punctured? Would that be over or under pressure?

Yep, I remember. Unfortunately, all I have with Retumbo is with the 175.

As far as the primer goes, my BWAG would be over over pressure.

 

[Idaho Trecker]

I've been out shooting more the last couple days and trying to figure out what is going on with some results I have been having... After consulting with Rich I was able to determine that I should kick myself for letting my excitement get the best of me. I was so excited to get this going and get data that I totally skipped some of the most basic steps for reloading... especially a wildcat! I after fireforming I was so excited to put some bullets downrange that I ASSUMED all my cases had shrunk after forming and were within specs... WRONG!!! I am using winchester brass until I get some Norma and after measuring my fireformed brass ranged from 2.510 to 2.540 and the max for the Sherman is 2.525". This explained why I blew a primer with only 59 grains of Retumbo. I measured that case and it was way long...
I learned a valuable lesson and hope that this can be a reminder to all levels the basics are very very important.

On to the good news...
I started over with all my reloading steps done correctly and started over with a ladder using RL 33 165 Matrix and remembering what pressure signs are with Rem actions. I have a very long throat on this rifle and am able to seat the bullets way out there. I am .020 off the lands and have a coal of 3.553"!!! I ran a ladder in 1 grain increments starting at 66 and ending with 72 grains. I dont have speeds yet but here is a picture of my results today

The target is at 388 yards. Through all the rounds fired the bolt lift was fine and the primers were all great until 71 and 72 grains I finally got a small crater around the primer. From the target it looks like I need to run some groups between 69 and 71 grains!

Once I get time to run some drops and figure out speed I'll update you. I also will be trying Retumbo, IMR7977 and possibly H1000. I would like to get my hands on some RL 26 but haven't been able to find any locally.

Just thought I would share my update.

 

[elkaholic]

Congrats Ryan, it looks like you have a shooter there! Don't feel too badly about your brass problem, the excitement of a new build can get to you (and me) With the top charge you are running, I'm betting you are in the 3150' range. I will be eager to see your chrono results........Rich

 

[trebark]

Congrats on a mighty fine build! Looks like you're off to nice start.

I have the same barrel except it's 30" and #7 contour in my .270 AI and mine stays pretty clean.

I didn't have much luck with Retumbo or RL33, so far H4831SC is best with IMR 7828SSC as a close 2nd for the 175. I have the IMR7977 but haven't had a chance to load any yet and perhaps do more testing with 165.

Keep us posted. Cheers!

Ed

Agreed. I think H4831SC would provide best results. Then maybe try H1000. Retumbo is likely too slow.

 

[elkaholic]

I totally disagree that Retumbo is too slow in this case! Remember, these are not 140-150 grain bullets. RL33 is Much slower than retumbo and I think you will be surprised when Ryan gets his chrono going. This case holds more than the A.I., especially with the throat it has for these bullets. He can compress about 74 grains of RL 33 behind the 165 Matrix. I can reach 3100+ with a 160 in the same case with a 6.5 bore and that with a 26" barrel. Ryan has considerably more capacity than mine because of the throat length, he is shooting only 5 more grains of bullet with a .013" larger bore and has a 27" barrel to boot. The chrono will be the judge, but I am betting that he will reach at least 3150'........Rich

 

[Idaho Trecker]

It is starting to look really promising that I'm going to have a speedster here. I will work on getting speed by figuring out drop over the next week by sending some rock chucks to acrobatics school . If I have time before fire season i would like to play with the 150 lrab just for fun... more trigger time.

 

[Idaho Trecker]

Its been a while since my last update... I made it to north Nevada and SE Idaho and completed my task of teaching some chucks acrobatics with the 270 Sherman and 165 Matrix!!! Needless to say the combo was devastating and I am very pleased with this gun.

I finally purchased a chrono (shooting chrony) and am now able to get in the ballpark with my speeds. It looks like I was right at 3000 fps with the 165 matrix and 69.7 grains of RL 33.

I jumped on the HBN train and got the rifle and bullets set up for it and the results were just like those of what others had posted on the very helpful HBN thread here on lrh. I made it out today and ran a ladder from 69.7, 71, 72, and 73 grains of rl33. I never ran into real pressure and the 73 grain load was compressed but I think I can get close to 74 grains crammed in there with the long COL and throat in my rifle.

69.7 2972
71 3071
72 3156
73 3151

I only ran this ladder at 200 yards (time constraints) but the vertical for 72 and 73 grains was only 1/4 inch.
When I get time again I'll run some groups. Even if I end up at 3150ish I wont be mad about that since it still puts me with 1344 ft lbs, 1915 fps, and only 19.4MOA drop(with 200 yd zero) at 1000 yards!!!

After talking with Elkaholic I picked up some RL26 and gave it a try with a ladder starting at 59grains up to 65 in 1 gr increments.

59 2935
60 2954
61 2998
62 didnt shoot
63 3056
64 3106 Cratered primer, click at top of bolt throw
65 3194 Cratered primer, click at top of bolt throw

The ladder wasnt spectacular but not bad either; however I will be sticking with rl 33 with the 165 matrix for velocity and accuracy. I think if berger ever releases the 170 they have talked about or I can get some 175 matrix the rl 26 may be a good choice for me.

 

[elkaholic]

Those are some impressive velocities Ryan! I've been guessing you would hit at least 3150, and it looks like you are there. That is some pretty serious long range medicine and Rhian (Bigngreen) has proven the effectiveness of the bullet on elk already. Move over 280 A.I.........Rich

 

[Idaho Trecker]

Those are some impressive velocities Ryan! I've been guessing you would hit at least 3150, and it looks like you are there. That is some pretty serious long range medicine and Rhian (Bigngreen) has proven the effectiveness of the bullet on elk already. Move over 280 A.I.........Rich

I was very impressed with the results and hope when I get time to verify the drops it all works out with the numbers I'm getting now.

 

[Idaho Trecker]

Also, when I say "ladder test" in my post I mean looking for max pressure. Just want to clarify so as to not offend anybody since I used the wrong terminology as on another thread I did.

 

[bigngreen]

WOW, that's looking promising to say the least! The 270 cal is really one of my favorites and the Sherman case and 165 Matrix is really doing it justice! Definitely following this Got some throating details, over all length?