338 Sherman Build (This Is My Boomstick!)

[benchracer]

This is my first experience with a wildcat cartridge of any kind, so there has already been something of a learning curve for me. Loading for the Sherman wildcats is not difficult, but it is different. I will detail what I have learned as this thread progresses.

When I initially started loading fire forming rounds, I attempted to use some of my Redding .30 cal sizers to neck up PRVI .270 brass. I am glad I started working with the less expensive brass, because I destroyed several cases in my initial attempts to neck them up. The lesson I learned is that a tapered expander is a good idea.

I ordered Hornady .30 and .338 neck size dies, which cured my problem, making it a snap to neck .270 or .280 cases up to .338 in two steps. I had previously acquired a .358 neck size die, in anticipation of using the false shoulder method to fire form, but it wasn't needed. On the right side of the photo, note the difference between the tear drop-shaped Hornady expander and the more abrupt Redding expander.

 

[benchracer]

I will be using Hornady 250 HPBT's to fire form my initial batch of brass, to be followed by testing with Berger 250 EH and Cutting Edge 252 MTH's.

I currently have 50 rounds each of PRVI and NORMA brass loaded with fire forming loads.

I now have 40 fire formed PRVI .270 cases and 25 fire formed Norma cases. The Hornady 250 HPBT's I used as fire forming bullets are BLUNT, to put it mildly. The OAL to the lands with this bullet is only 3.332". In contrast, the OAL to the lands with the Bergers is 3.575". Hornady claims a .675 g1 bc for this bullet. I don't think so...

Above are fire forming loads with the Hornady 250 HPBT, along with examples of formed cases. Norma brass is on the left, PRVI on the right. I charged the cases with some H-380 that I wanted to burn up and seated the bullets for a .020 jam.

Here, again, I ran into something to add to my "Lessons Learned" file. The H-380 had been in my possession for about ten years. I had a partial pound in one can, and a full pound in the other can (which was still factory sealed). I loaded the Norma brass with a middling powder charge, using Hornady 338-06 data, from the can that had been factory sealed, and produced nicely formed cases without incident.

I had loaded the PRVI cases from the partial can of powder, using the same powder charge as the Norma cases, and encountered ejection marks, heavy bolt lift, and sticky extraction, immediately. I discontinued firing these rounds until I could pull the bullets and reduce the powder charge. I reduced the powder charge by approximately 10% and was able to proceed with fire forming without further incident.

It appears that the powder in the opened can of H-380 had dried out somewhat with the passing of time, speeding up the burn rate. So noted...

I hope to complete fire forming and barrel break-in next weekend.

 

[benchracer]

During the planning phase for this build, Rich and I had discussed use of RL-26 with the 250's. However, the initial results with Rich's 338 were not what we had hoped for. He had much better luck with RL-17 and Hybrid 100V. After discussing the matter, it seemed likely that the disappointing initial results with RL-26 may be caused by an ignition problem. With that in mind, I will give RL-26 another go, using different brands of mag primers, in hopes of getting the results we were hoping for.

Though my Saturday shooting session was cut short by a thunderstorm, I did manage to fire form enough Norma brass to perform a quick pressure runup with RL-26, Berger 250 EH's, and three brands of magnum primers. I determined that the maximum charge of RL-26 that would fit in the case was 72.0 grains. I backed down to 68.0 grains and loaded five rounds for test, at one grain increments, up to 72.0 grains, with each of the three magnum primers tested: CCI, Winchester, and Federal 215 Match.

The batch loaded with CCI primers exhibited erratic behavior. The initial round clocked in the low 2700's, velocity peaked @ 2785 on the third round, and the velocity decreased with the fourth and fifth rounds.

Things got more interesting with the Winchester primers. The first round clocked 2729 and the last round clocked 2852, with a faint ejector mark.

The Federal 215M's performed similarly, with the first round measuring 2735 and the last round measuring 2858, again with a faint ejector mark.

It looks like the formed PRVI cases will hold an additional 1.5 grains of RL-26. I plan to test them to their max capacity with the Winchester and Federal primers.

 

[codyadams]

Should be interesting, what was rich getting with rl 26 in his 24"? How much difference do you think your getting?

 

[benchracer]

Should be interesting, what was rich getting with rl 26 in his 24"? How much difference do you think your getting?

IIRC, standard primers were used during Rich's testing. Results were erratic, with velocity topping out in the mid-2700's, and Rich mentioned that it behaved like there wasn't enough initial pressure to make the combination work. That is one reason I decided to re-visit RL-26 using magnum primers.

I still don't know enough to say, one way or the other, if it will work. The best answer I have right now is maybe.

ETA: I spoke with Rich and hope he will re-visit the 250 EH/RL-26 combo using magnum primers. It would be useful to see if he can confirm my results.

 

[benchracer]

Very nice benchracer. Always nice to see a Ruger build!

I am fond of controlled feed rifles and I like doing something a bit different from the norm. The long action Sherman cartridges are probably best suited to a Remington 700 or an action for which an extended mag box is available. There are some trade-offs to going the Ruger route, but I understood that going in. I am glad you like the build!

 

[benchracer]

It's a journey you will enjoy with the new round. I've never tried cutting edge bullets (cost and inflated bc' s) as for the 250 Berger it has the bc and weight but I've had to many Berger fails. I think rich is on the right track with the accubond for his rig. I'll be interested to see if mag primers solve the Rl26 problem. I personally think the bore size is why the 100v burn rate has worked best. My 300 SS with 225 eld m and rl26 are nearly maxed out on capacity and pressure.

The CE bullets are definitely not inexpensive to shoot, so I won't be plinking with them anytime soon! Having said that, they offer something unique in certain applications. While it is true that some of their bc's are inflated, CE has had Applied Ballistics test some of their bullets. The CE 252 grain .338 is one that has an AB-verified bc attached to it. OTOH, I did some work with the .375 300 grain MTH awhile back. The bc, as stated by CE, was .750, though the real world bc is in the mid-.600's. Even at that, there is no other 300 grain .375 bullet that comes close to its performance. It still offers a wide advantage over anything else in its class, though I dearly wish it did have a .750 g1 bc!

I have yet to shoot a Berger at anything but paper, so I don't have any personal experience to go by. Though the .338 250 EH seems to be mostly overshadowed by its 300 grain big brother, I have heard good reports about its performance, and am prepared to believe them, for now.

As for the Accubonds, though I have no doubt they are good bullets, I intend to use 200 grain class cup and core bullets primarily in pursuit of lighter game, such as deer and pronghorn. I personally desire a more explosive bullet for that, which is why I am looking at the SST. It should also make for an inexpensive practice bullet.

The 200 grain CE is my take on an old recommendation by LongTimeLongRanger for the .338 WinMag. He advocated Barnes 185 TTSX, driven hard, as an all-around choice out to 700 yards or so. I believe I can equal or better that performance from the 338 Sherman, with a load that will mag feed from my Ruger.

I don't know, yet, if the mag primers will make RL-26 work. I believe you are correct in stating that the issue is bore diameter. However, the crux of the matter is the question of how much capacity, relative to the bore diameter, is required for RL-26 to offer an advantage. Whether or not the Sherman offers enough capacity is the open question I am trying to answer.

If I had to bet money today, I would bet that the optimum combination for 250 grain bullets proves to be RL-17/Hybrid 100V and RWS brass. The only way to really know is to test...

 

[codyadams]

I do think RL-17 would be a good option, I have not played with Hybrid 100v but have heard a lot of good things about it. I'm sure you know, but keep in mind RWS brass, while very tough, tends to be a lot heavier than other brass with a smaller capacity, so work up low.

With the RL-26, are you using a drop tube? I use a 6" drop tube for it in my .260 AI, and even in that smaller cartridge, pouring slowly into the drop tube it gave me an extra 2 grains of capacity with the same compression as just dumping into the brass with a standard funnel. RL-26 seem to respond very well to a drop tube. If you aren't already trying this, I certainly would if you aren't able to pressure out with it. An extra 2-4 grains in that larger case may be what you need to do it.

As far as the Ruger action, you should be able to run everything right out near the lands and still fit in the magazine accept the Berger 250 and possibly the CE bullet, I do not know as I am not familiar with this bullet. I believe the mag length of the M77 300 win mag I have is 3.430". I was able to modify my bolt stop and case ejector enough to single load rounds out to about 3.650 or 3.700", I would have to review my notes to know exactly. But I remembered when I attempted to load rounds long with the 215 Bergers, I went to single load them and upon attempting to eject a loaded round it would not eject. You have to push the loaded round back into the mag, and possibly open up the loading gate or pull the bolt and dump the round out of the rear.

If you want to single load these and you can't get your 3.575" Berger loads or whatever length the CE loads end up being to eject, it is a pretty simple fix. Remove the bolt stop and take some material off the face of it, where the recoil lug hits, so the bolt will come back far enough to allow the round to eject, But make sure you don't take off so much that it no longer engages the recoil lug. Now, remove your ejection bar (not sure if that's the technical name, but the piece that pushes the case out of the bolt face) and take a small amount off of the face of this piece. Go slow on this part, I have not seen how much I can take off without hindering reliability, but to me it looks like if you take off too much it will mess up ejection. Only take off as much as you need. I was able to gain a good amount of room for ejection by doing this, and I ran some dummy rounds through as well as some empties at a fast speed and ejection was reliable.

 

[benchracer]

I do think RL-17 would be a good option, I have not played with Hybrid 100v but have heard a lot of good things about it. I'm sure you know, but keep in mind RWS brass, while very tough, tends to be a lot heavier than other brass with a smaller capacity, so work up low.

You are quite right. Rich's work with RWS has shown it has lower capacity, but that is less of an issue with RL-17/Hybrid 100V, and the reduced capacity has shown itself to be offset by superior ability to handle pressure. RWS brass would rule out use of RL-26, though, so Norma or PRVI would have to be used for that.

With the RL-26, are you using a drop tube? I use a 6" drop tube for it in my .260 AI, and even in that smaller cartridge, pouring slowly into the drop tube it gave me an extra 2 grains of capacity with the same compression as just dumping into the brass with a standard funnel. RL-26 seem to respond very well to a drop tube. If you aren't already trying this, I certainly would if you aren't able to pressure out with it. An extra 2-4 grains in that larger case may be what you need to do it.

I have been using a 6" drop tube with RL-26. The loads I have assembled, using RL-26, are highly compressed loads. I am using every kernel of powder I can fit in the case, for sure!

As far as the Ruger action, you should be able to run everything right out near the lands and still fit in the magazine accept the Berger 250 and possibly the CE bullet, I do not know as I am not familiar with this bullet. I believe the mag length of the M77 300 win mag I have is 3.430". I was able to modify my bolt stop and case ejector enough to single load rounds out to about 3.650 or 3.700", I would have to review my notes to know exactly. But I remembered when I attempted to load rounds long with the 215 Bergers, I went to single load them and upon attempting to eject a loaded round it would not eject. You have to push the loaded round back into the mag, and possibly open up the loading gate or pull the bolt and dump the round out of the rear.

If you want to single load these and you can't get your 3.575" Berger loads or whatever length the CE loads end up being to eject, it is a pretty simple fix. Remove the bolt stop and take some material off the face of it, where the recoil lug hits, so the bolt will come back far enough to allow the round to eject, But make sure you don't take off so much that it no longer engages the recoil lug. Now, remove your ejection bar (not sure if that's the technical name, but the piece that pushes the case out of the bolt face) and take a small amount off of the face of this piece. Go slow on this part, I have not seen how much I can take off without hindering reliability, but to me it looks like if you take off too much it will mess up ejection. Only take off as much as you need. I was able to gain a good amount of room for ejection by doing this, and I ran some dummy rounds through as well as some empties at a fast speed and ejection was reliable.

I am very interested in modifying my bolt stop and ejector. The Berger 250 is just long enough that it won't eject a loaded round. That was something of a surprise to me. Dimensionally speaking, I think of the 77 Mark II as, basically, a commercial mauser. Prior to receiving my finished rifle, I made a dummy round and ran it through one of my commercial mausers, without issue.

After experimenting with my Ruger, I had been wondering if bolt stop modifications might be an answer. One thing I had noted is that the Berger 250 laid neatly on the feed ramp. It would easily accommodate one round laid on the feed ramp and another in the chamber. I just hesitate to do that unless I know I can eject a loaded round.

Thank you for sharing the results of your modifications. That gives me something to think about...

 

[benchracer]

Finished fire forming today. I now have 50 Norma and 50 PRVI cases ready to go. Next step will be establishing max with each bullet and powder. I hope to be tuning loads by next Sunday.

During the fire forming process, there have been quite a few 5+ shot groups hovering around MOA, out to 200 yards. This is with NO load development. This rifle acts like it really wants to shoot. I can't wait to see what it does when the tuning starts.

 

[RockyMtnMT]

The CE bullets are definitely not inexpensive to shoot, so I won't be plinking with them anytime soon! Having said that, they offer something unique in certain applications. While it is true that some of their bc's are inflated, CE has had Applied Ballistics test some of their bullets. The CE 252 grain .338 is one that has an AB-verified bc attached to it. OTOH, I did some work with the .375 300 grain MTH awhile back. The bc, as stated by CE, was .750, though the real world bc is in the mid-.600's. Even at that, there is no other 300 grain .375 bullet that comes close to its performance. It still offers a wide advantage over anything else in its class, though I dearly wish it did have a .750 g1 bc!

I have yet to shoot a Berger at anything but paper, so I don't have any personal experience to go by. Though the .338 250 EH seems to be mostly overshadowed by its 300 grain big brother, I have heard good reports about its performance, and am prepared to believe them, for now.

As for the Accubonds, though I have no doubt they are good bullets, I intend to use 200 grain class cup and core bullets primarily in pursuit of lighter game, such as deer and pronghorn. I personally desire a more explosive bullet for that, which is why I am looking at the SST. It should also make for an inexpensive practice bullet.

You should give our 213g Hammer Hunter a go. It was designed to be a balance between higher vel and a decent bc. It is the bullet that I will be hunting with this fall. The g7 bc that I have from shot drops is .266. This should be pretty close to .542 g1. I am very excited about this bullet. Short baring surface and our PDR design make pressures very low increasing muzzle vel significantly over conventional bullets of like weight. With the aggressive design the bc is pretty good. In my rifle I can run them at 3500fps and the out run everything else to 1000y for drop and hang very close for wind. Within a couple of inches. Because of the higher muzzle vel the point bland range increases by about 30-50 yards over other bullets.

Steve
The 200 grain CE is my take on an old recommendation by LongTimeLongRanger for the .338 WinMag. He advocated Barnes 185 TTSX, driven hard, as an all-around choice out to 700 yards or so. I believe I can equal or better that performance from the 338 Sherman, with a load that will mag feed from my Ruger.

I don't know, yet, if the mag primers will make RL-26 work. I believe you are correct in stating that the issue is bore diameter. However, the crux of the matter is the question of how much capacity, relative to the bore diameter, is required for RL-26 to offer an advantage. Whether or not the Sherman offers enough capacity is the open question I am trying to answer.

If I had to bet money today, I would bet that the optimum combination for 250 grain bullets proves to be RL-17/Hybrid 100V and RWS brass. The only way to really know is to test...

 

[elkaholic]

Should be interesting, what was rich getting with rl 26 in his 24"? How much difference do you think your getting?

I just tested out RL26 again with WW mag primers and ran 70-72 grs. with a 215 Berger over the mag speed. Looks like the mag primers are the answer although I can't get quite enough powder in to max it out. That does not mean it might not end up being a good choice? Seems Brad got about 26' more mv with 2" extra barrel. That is about what we were thinking. I estimated maybe 15' per inch? Below are the results on the mag speed......Rich

IIRC, standard primers were used during Rich's testing. Results were erratic, with velocity topping out in the mid-2700's, and Rich mentioned that it behaved like there wasn't enough initial pressure to make the combination work. That is one reason I decided to re-visit RL-26 using magnum primers.

I still don't know enough to say, one way or the other, if it will work. The best answer I have right now is maybe.

ETA: I spoke with Rich and hope he will re-visit the 250 EH/RL-26 combo using magnum primers. It would be useful to see if he can confirm my results.

Here is your confirmation!! I loaded 70-72 grains RL26 behind a 250 Berger with a WM primer. Looks like about 13' per inch more velocity with your 26". I think we figured about 15'. Below are the velocity results and an Elderberry tree that got in the way

 

[benchracer]

I just tested out RL26 again with WW mag primers and ran 70-72 grs. with a 215 Berger over the mag speed. Looks like the mag primers are the answer although I can't get quite enough powder in to max it out. That does not mean it might not end up being a good choice? Seems Brad got about 26' more mv with 2" extra barrel. That is about what we were thinking. I estimated maybe 15' per inch? Below are the results on the mag speed......Rich


Here is your confirmation!! I loaded 70-72 grains RL26 behind a 250 Berger with a WM primer. Looks like about 13' per inch more velocity with your 26". I think we figured about 15'. Below are the velocity results and an Elderberry tree that got in the way

Well, there you have it: 338 Sherman, Fire Breathing Wildcat and Slayer of Unwary Elderberries! Glad to see the RL26 results confirmed. Thank you, Rich!

 

[elkaholic]

Well, there you have it: 338 Sherman, Fire Breathing Wildcat and Slayer of Unwary Elderberries! Glad to see the RL26 results confirmed. Thank you, Rich!

I couldn't help it! Never bagged an elderberry with a 338