Loading the SS-109 with Winchester 748

[David2011]

Most of my shooting is with cast boolits but I just can't bring myself to cast those itty bitty boolits for my AR-15. I had purchased some time ago two bags of SS-109 steel core penetrators to load up and hope I never need.

There were pitfalls along the way. If you just want the results please scroll to the bottom. If you want to know how I got there, read on!

I searched the web at length looking for solid information on 748 and the SS-109 without finding much and some of what I found was fairly sketchy looking. I'm packing up my reloading room to move several hundred miles and kept some 748 out to load the SS-109s because I had excellent results with 748 and the 50 grain V-Max. I also had H335, BL-C (2), Varget and most of the usual powders but they were already packed. I have a lot of reloading manuals but of course none of them list the SS-109. Other bullets at or near the same weight had a very wide range of powder charges with 748; too wide to draw any solid conclusions.

• Hornady shows loads for 60-62 grain bullets of various designs and lists a starting charge of 22.1 grains at 2700 fps and a maximum charge of 25.5 grains with a velocity of 3100 fps. That just didn't look right based on my use of 748 and other bullets. No pressure was listed.
• Hodgdon shows a starting load of 22.3 grains at 2,779 fps and a max charge of 24.0 grains at 2,967 fps with a pressure of 52,400 PSI.
• My Sierra manual has their 63 grain SMP add 65 grain SBT bullets lumped together in their AR-15 specific pages. They call for a starting load of 24.3 grains for 2600 fps and a maximum charge of 25.9 and 2800 fps. No pressure data is provided.
• The Lyman #49 shows a 63 grain SMP and a starting load of 24.7 grains with a velocity of 2768 fps and a maximum charge of 27.5 grains at 3,142 fps. Pressure was listed at 49,300 CUP.

Now, none of these bullets are the SS-109 so all I can do is look at comparable weight bullets. The SS-109 is long for its weight due to the steel core. The load data for similar weight bullets varied widely as did velocity predictions. I don't think I have ever seen such a wide spread of recommendations and predictions for a narrow range of bullet weights. I was hoping to just load and go without doing load development but the Internet forum recipes varied as wildly as the reloading manuals so I gave in to doing some testing. I would ordinarily not take this approach to any handloading but I was up against time, cold temperatures and very windy conditions during my window of opportunity. The brass was sized, decapped and cleaned in a citric acid solution to remove the dark brown patina. It was then trimmed to length and the primer pockets were either swaged with a Dillon swage or reamed with a Hornady primer pocket reamer to remove the crimp, depending on my mood on the day a batch was processed. I bought 3,000 surplus Lake City military 5.56 cases and it took a while to process all of them. Case mouths were chamfered inside and out.

The first bag of SS-109s I loaded was based on starting charge information and I unfortunately loaded way too many (about 250 rounds) before deciding to do a ladder test. I just got more and more uncomfortable with the starting load as I researched further. The first bag of SS-109 bullets were at best, inconsistent in the point shape causing the OAL to vary about .015"-.020" so I had to adjust the seating die to keep everything under 2.260" OAL since these rounds would go in Ar-15 magazines. My target OAL was 2.258" just to make sure they would work in any magazine. For that reason I reduced my starting charge to 23.4 grains because of seating depth concerns. A second bag of SS-109s from a different source proved to not only look more consistent but proved to be much more consistent while loading with OALs varying about .005" from shortest to longest; a tolerance I found quite acceptable for SS-109s. These aren't competition target loads. They're crisis management loads. I don't consider myself a prepper but I lived in southeast Louisiana when Katrina hit so I'm going by the Boy Scout motto: "Be Prepared."

Utimately, I loaded up 5 rounds each of 5 powder charges using new SS-109s, Winchester Small Rifle Primers, Winchester 748 and the mixed Lake City surplus brass. All ladder test charges were thrown by an RCBS Chargemaster 1500 and loaded on a Rock Chucker II.

No attempt was made to check for accuracy due to the 20+ mph crosswind at the range. It was better than the 40+ gusting to 60 a couple of days earlier. My target behind the chronograph was a metallic silhouette pig at 200 yards and I had no trouble hitting it with any of the rounds. I just wanted to determine if all of the loads would function the rifle properly and if any exhibited signs of excessive pressure.

I noticed during the first string of 23.4 grain loads that I was getting a BAT notice on the chronograph. I had to wait for a cold range so I could change the battery but there was no data for that first string. It ended up not being very important. The rounds at 23.4 grains did cycled normally on a short gas system. After a battery change the chronograph worked as expected and the test went without further interruption.

Rifle used: AR-15, 16" barrel, 1:9 twist, 5.56 NATO chamber
Temperature was 65 degrees F, Humidity 18%, Elevation 3700'


Results:

Charge - ES - SD - Average - Comments

24.0 - 77 - 32 - 2542 Hornady predicted 2967 fps for this load

25.0 - 33 - 12 - 2677 Lyman predicted 2768 fps for 24.7 grains

26.0 - 35 - 15 - 2813

27.0 - 38 - 15 - 2908

Lyman predicted 3142 fps for 27.5 grains. I did not test 27.5 grains.

Conclusion: The data for commercially produced bullets in the 60-65 grain range was for the most part very conservative for the charge weights and excessively optimistic for the velocities. At 27.0 grains the primers were still rounded with no significant flattening. There is probably a slightly reduced radius but it would take an optical comparator to tell just how much. The corner of the primers is not even close to square at 27.0 grains.

I pulled all of the bullets for two batches of loads, using all of the first bag and a few of the second bag of bullets and recovered the powder. The bullets were pulled with an RCBS press mounted collet puller so they can be used again. The rounds will be reloaded with 27.0 grains of 748 and stored in a USGI ammo box which is air tight.

[rsrocket1]

Wow, TMI for most, but it was perfect for me.
Quick observations/notes: What barrel length was used in the Hornady and Lyman data? I'm guessing it was probably 24" and not 16'
Quickload predicts 24.0g 748, S-109 63g fmj seated to 2.258" 24" barrel MV = 2997 Peak pressure = 47754.
With a 16" barrel, QL predicts MV = 2721 fps. QL lists the bullet length of 0.866" which leads to a seat depth of 0.367". This does not take into account any losses in velocity due to a gas operating system and it also assumes the case volume to be 28.8g H2O. Most actual measurements of .223/5.56 show a case volume of 30 to 30.6g H2O which will also drop peak pressures and MV's.

The most important thing to do is to do the ladder test so that was good for you. Stop when you reach acceptable accuracy for your gun and application, then load up however many rounds you need. If you are really into "prepping", do the test with rounds heated up to 100F and cold soaked down to freezing or whatever the low extreme you will expect to use these rounds in and see if the accuracy is still acceptable.

I'm guessing the need for "defensive rounds" at 200 yards not needing to be any better than "minute of zombie" or about 4 MOA at that range and if you have your elevation adjusted properly, just about anything that goes bang will be adequate.

I made a bunch of paper punching m193 rounds and have settled on 26.2g 748 for the 55g fmjbt. This load produces 1 to 1.75 MOA out of both a 16" Ruger American Ranch and 20" AR using range pickup brass. It's a good metering powder, great for range fodder. It is deadly on soda cans at 150 yards or 2 liter soda bottles at 200.

Your ES's and SD's are very good. Don't forget the desiccant bags in the ammo box. If you're really cheap you can use and old (clean) sock stuffed with uncooked rice. I also prefer stripper clips rather than loose rounds that can rattle around the box and cause setback of the bullet.

[5Shot]

I was loading 60 grain Vmax with WC844 (burns like H335/Win 748) and I ended up with a load of 25.5 in my rifle. I'd not go as high as the Lyman manual shows.

[Larry Gibson]

I've chronographed several different lots of M855 out of several different 20" ARs and M16A2s with 7 and 9" twists. The M855 (US loaded with 62 gr SS109 type bullets) lot averages runs right around 2950 to 2980 fps. You'll lose probably 75 to 100 fps, depending on lot, with your 16" barrel.

I believe the Lyman velocities you list are out of their 24" test barrel.

I have worked up loads with pulled M855 bullets, 748 powder, LC cases and WSR primers. I found, in my Colt AR with a 20" barrel having a 9" twist that 26.5 gr duplicates the velocities of M855 issue ammunition. Accuracy is also quite comparable. I also pressure tested that load (Contender 21" test barrel w/Oehler M43 PBL) with that M855 bullet and the Hornady 62 gr FMJBT. Both gave average psi's in the 56 - 57,000 psi range. A test of one lot of US M855 gave comparable velocity in the 21" test barrel but at 62,300 psi (that is about the current MAP level for M855 ammunition). A lot of Canadian M855 ran about 100 fps slower at 60,000 psi.

[David2011]

Larry, I believe you are correct regarding the 24" barrel length for Lyman testing. There is no information on the Hornady page about the test rifle. It's a page from the Hornady updates that have not been published in a book yet.

Wow, TMI for most, but it was perfect for me.
Quick observations/notes: What barrel length was used in the Hornady and Lyman data? I'm guessing it was probably 24" and not 16'
Quickload predicts 24.0g 748, S-109 63g fmj seated to 2.258" 24" barrel MV = 2997 Peak pressure = 47754.
With a 16" barrel, QL predicts MV = 2721 fps. QL lists the bullet length of 0.866" which leads to a seat depth of 0.367". This does not take into account any losses in velocity due to a gas operating system and it also assumes the case volume to be 28.8g H2O. Most actual measurements of .223/5.56 show a case volume of 30 to 30.6g H2O which will also drop peak pressures and MV's.

The most important thing to do is to do the ladder test so that was good for you. Stop when you reach acceptable accuracy for your gun and application, then load up however many rounds you need. If you are really into "prepping", do the test with rounds heated up to 100F and cold soaked down to freezing or whatever the low extreme you will expect to use these rounds in and see if the accuracy is still acceptable.

I'm guessing the need for "defensive rounds" at 200 yards not needing to be any better than "minute of zombie" or about 4 MOA at that range and if you have your elevation adjusted properly, just about anything that goes bang will be adequate.

I made a bunch of paper punching m193 rounds and have settled on 26.2g 748 for the 55g fmjbt. This load produces 1 to 1.75 MOA out of both a 16" Ruger American Ranch and 20" AR using range pickup brass. It's a good metering powder, great for range fodder. It is deadly on soda cans at 150 yards or 2 liter soda bottles at 200.

Your ES's and SD's are very good. Don't forget the desiccant bags in the ammo box. If you're really cheap you can use and old (clean) sock stuffed with uncooked rice. I also prefer stripper clips rather than loose rounds that can rattle around the box and cause setback of the bullet.

Comparing my chrono data to Quickload there is still a fair amount of discrepancy from source to source. That's why I included all of the background to this load development. Since the loads will be housed on the Texas Gulf Coast I'm not too worried about testing in very cold weather. Minute of Zombie is adequate anyway. I was pleased and surprised at how consistent the ES and SD data was. The Chargemaster is as accurate and consistent as my beam scales. I had the opportunity to use a friend's Chargemaster for several months before I bought one and was surprised at how good it was.

I have some 53 grain Sierra Match Kings loaded for accuracy and used in competition to 300 yards. That load is 26.7 grains of 748, so very consistent with your 55g fmjbt. It produces groups in the .400" range at 100 yards.

The rifle I used for this testing is strange. It shoots premium bullets extremely well but I've tried several brands of "popular priced" factory loads and it shoots patterns of 3"-4". This is the second factory barrel on this rifle. The first one was very accurate as well but the chamber caused a bulge in the brass just above the web. It was replaced at no charge and the new barrel is just as accurate as the original one. Neither barrel liked cheap factory ammo and neither is very accurate with 55 gr. FMJBTs, even from the good bullet manufacturers. I've tried 748, 335, 3031, BL-2 (C) and Varget with several brands of primers with the FMJ bullets and nothing shoots well. One explanation I've read is that the FMJ jacket is trimmed and then wrapped around the base of the bullet which can cause an out of balance bullet but that doesn't explain why the same Remington or American factory loads shoot much better in another rifle.

[David2011]

I was loading 60 grain Vmax with WC844 (burns like H335/Win 748) and I ended up with a load of 25.5 in my rifle. I'd not go as high as the Lyman manual shows.

I was skeptical about the upper Lyman loads but the chronograph and the spent cases indicate a reasonable velocity and no signs of excessive pressure. I normally load for accuracy but for the SS-109 I just wanted good function and upper range but not top range velocity.

[rsrocket1]

The rifle I used for this testing is strange. It shoots premium bullets extremely well but I've tried several brands of "popular priced" factory loads and it shoots patterns of 3"-4".

I've also found that certain factory loads more accurate than others and it does not necessarily follow price. My AR absolutely loves PMC Bronze @ $6/20 and can shoot near clover groups at 100 yards but doesn't do anywhere near as well with some other more expensive factory ammo.



The Ruger doesn't seem to like any of the factory ammo I've fed id so far but can give me very good groups with 223bulkbullets at 7 cents apiece. Even with a hot barrel, the groups don't open up too much.

[beltfed]

ONe thing we learned on State Service rifle team in early days
of shooting the AR-15s: Shooting 25.5 gr 748 under 69 Sierras.
Accurate, BUT:
748 powder fouls the carrier group. You need to de-carbon it frequently
We turned to Varget--24.6 gr under Hornady 75 s. the problem went away and we got match grade,
Camp Perry winning accuracy and even hundreds of rounds w/o fouling the carrier/gas system
Practice loads with the SS109s from IMI were also very accurate in our 1:8 twist rifles
over Accurate 2520 or BC-2. but again, you need to clean the carrier more
beltfed/arnie

[beltfed]

ONe thing we learned on State Service rifle team in early days
of shooting the AR-15s: Shooting 25.5 gr 748 under 69 Sierras.
Accurate, BUT:
748 powder fouls the carrier group. You need to de-carbon it frequently
We turned to Varget--24.6 gr under Hornady 75 s. the problem went away and we got match grade,
Camp Perry winning accuracy and even hundreds of rounds w/o fouling the carrier/gas system
Practice loads with the SS109s from IMI were also very accurate in our 1:8 twist rifles
over Accurate 2520 or BC-2. but again, you need to clean the carrier more
beltfed/arnie

[nagantguy]

ONe thing we learned on State Service rifle team in early days
of shooting the AR-15s: Shooting 25.5 gr 748 under 69 Sierras.
Accurate, BUT:
748 powder fouls the carrier group. You need to de-carbon it frequently
We turned to Varget--24.6 gr under Hornady 75 s. the problem went away and we got match grade,
Camp Perry winning accuracy and even hundreds of rounds w/o fouling the carrier/gas system
Practice loads with the SS109s from IMI were also very accurate in our 1:8 twist rifles
over Accurate 2520 or BC-2. but again, you need to clean the carrier more
beltfed/arnie

Your findings match our own; right down to the IMI being some of the most accurate “surplus “ ammo I’ve ever used . And double down on Varget being very clean burning and consistent; 748 seems to leave self reproducing carbon build up; and it’s as bad in mini 14s as it is in AR/M16 family

[rsrocket1]

Some better groups with 26.3g 748 under the 55g fmjbt. This time they were excellent in both the 16.12" Ruger ARR and the 20" AR-15. Both are 5 shot groups from sandbags at 100 yards.



And equally as good was that the 26.6g load opened up quite noticeably so I know the sweet spot is right around 26.0 and 26.3 with 26.3 being sub MOA in both the AR and Ruger.

This was with PMC brass. The next tests will be using different matched brass, then with mixed brass.

[skeettx]

Watching, thank you for sharing
Mike