2400 in a Savage 10FCM Scout

[Boomer Mikey]

I went the range Sunday for round 2 of testing with my Savage 10FCM 308 Scout rifle and 2400 powder. Round 1 consisted of loads from 16 grains to 19.5 grains with bullets cast from my existing RCBS 30-165-SIL and 30-180-SP molds.

This time I repeated loads from 17.5 grains up to 19.5 grains with 165’s and included bullets from a new RCBS 30-200-SIL mold instead of the 180-SP’s used previously.

Bullets were seated to 2.725” COL for the 165’s and 2.850” for the 200’s. Bullets were also crimped in place with a Redding 308 taper crimp die to remove the case mouth flare and provide improved feeding and improved ignition… not that it’s a factor using 2400 but a standard operation with my loads. Bullets engraved the rifling in the throat lightly, feed from the removable magazine well, and loaded cartridges can be un-chambered without pulling bullets.

Match prepped WW brass, LBT Blue lube, and WLR primers. Bullets were cast from new molds using 50/50 WW/LINO alloy and water quenched to produce BHN 21 bullets that were sized to 0.310” for the rifle's 0.308" groove diameter bore.

Loads consisted of 2400 powder in ½ grain increments from 17.5 grains to 21 grains for both bullets and velocities from the 20.5" barrel ranged from 1623 fps to 1934 fps. 50 yard accuracy ranged from .7" to 1-1/2" with most groups in the 1"- 1.25" range and results proved repeatable.

The rifle wasn't cleaned during the 100 round testing period in 88 degree weather. No leading issues... 2 wet patches and 10 strokes with a patch covered brush using Shooter's Choice was repeated once for a total of 20 strokes which produced a clean bore.

The Simmons 2X20 IER 1" scope on the rifle in Leupold "QRW" rings is fine for snap shooting but not the best for target shooting. I’ll mount a 10X or 2-7X scope on the rifle for the next testing session to see if I can eliminate some of the single fliers from some otherwise nice groups and vertical stringing that may have been from mirage… and to get ready for long range testing.

I just picked up an 8# jug of 2400 for the next round of testing. Quickload predicts 25 grain loads will reach 2158 fps@42414 psi and 27.5 grain loads 2289 fps@51659 psi.

Round 3 will repeat 21 grain loads and run loads up the ladder to the 25 grain load level.

Round 4 will run loads up the ladder to the 27.5 grain load level if things stay together group-wise?

Final work will be to run ladder tests on the sweet spots and long range testing out to 200 meters.

This is my first experience using 2400 in cast bullet rifle loads but it won’t be my last…

Boomer :Fire:

[Boomer Mikey]

I went to the range Sunday with loads for round 3... 21 - 25.5 grains of 2400 in Winchester cases with WLR primers and 173 grain RCBS 165-SIL and 205 grain 200-SIL bullets. LBT Blue soft lube. All bullets were chambered from the removable magazine.

The RCBS 30-165-SIL bullets fit the bore snugly with a 0.302" nose and 0.310" body. The 30-200-SIL has a tapered nose from 0.299" to 0.308" and the body was sized to 0.310" for the rifle's 0.308” perfectly smooth groove diameter. Bullets were water dropped and measured 21 BHN. Bullets were not weighed or sorted to any criteria other than coming from the same casting session.

Groups remained consistent until 45,000 PSI was passed with the 200's. The 173's shot best right at 40-45,000 PSI levels and the 200's showed equal results at or below 45,000 PSI. Pressure signs on primers are normal for 45-50,000 PSI loads. 173's @ 2175 fps and 205's @ 1975 fps will work fine for CB rifle silhouette.

I didn't clean the rifle during the 125 round session and It actually shot better as it got hotter... some of the best groups were the last at the highest velocity of 2200 fps in 90 degree weather. The rifle was cleaned at the end of the day with no leading present. Two wet Shooter's Choice patches followed by ten strokes with a patch covered brush repeated three times produced a clean bore.

I changed scopes to a 2-7 power Burris handgun scope mounted on the scout rail forward of the ejection port. After shooting for a while I notice several groups with two groups in one, then I realized there was a parallax issue at 50 yards.

Next time out I'll split powder charges into .25 grain steps between 24.5 and 25.5 grain loads for the 165's and 200's charges between 23.5 and 24.5 grains and testing will move out to 100 yards.

http://castboolits.gunloads.com/attachment.php?attachmentid=7990&d=1215461483

This is a nice, handy rifle that carries as well as it shoots.

Boomer :Fire:

[GabbyM]

Nice set up Boomer.
The older I get the more I like lighter rifles.
When I looked at the Savage web site they list the 308 as a 1-10 twist. So what happend to that theory I've read about 1-10 twist not shooting that fast? Are those RCBS boolits majic pills?

I like the looks of those big ones. Do you have a preference yet?

[Boomer Mikey]

Nice set up Boomer.
The older I get the more I like lighter rifles.
When I looked at the Savage web site they list the 308 as a 1-10 twist. So what happend to that theory I've read about 1-10 twist not shooting that fast? Are those RCBS boolits majic pills?

I like the looks of those big ones. Do you have a preference yet?

Yes, it's a 1:10 twist; the bullets and the relatively fast burning 2400 powder don't know better I guess.

The rifle has had a small amount of fire-lapping (10 rounds) to smooth out a few machine marks and has never seen a jacketed round other than the factory proof test.

IMO if I get the 200 grain bullets harder they'll continue to shoot faster with accuracy but this is all the power I need. I like the 200's for their BC and delivered energy at 200 meters. I'll weight sort a batch to see if they'll group better for 500 meters. IMO the 165's (173 grains) will do everything fine with accuracy out to 200 meters.

The magic of the RCBS 30-165-SIL is that my new mold produces bullets with a 0.302" nose in my alloy. I haven't tried the 30-200-SIL in any other rifle but IMO it will work well because of it's tapered nose design. I really want to see what the 200 will do in my 30-06.

This is a fun rifle to shoot and these loads don't beat me up.

Thanks,

Boomer :Fire:

[runfiverun]

the rcbs does like to be in the 1950 or so range, the lube you are using is helping.
i would be interested in hearing how they do at 100 yds at a velocity of 2200 or so.
the 302 nose is definately a big help though.

[Boomer Mikey]

the rcbs does like to be in the 1950 or so range, the lube you are using is helping.
i would be interested in hearing how they do at 100 yds at a velocity of 2200 or so.
the 302 nose is definately a big help though.

The next full grain step up using 2400 will reach 2200 fps but exceed 45,000 PSI. I believe the accuracy will go away with one more grain because the pressure will exceed my alloy's strength. One more factor is that I'm sizing and crimping gas checks nose first, then lubing in the normal manner.

Just for experimental purposes... I may assemble another set of loads using Accurate 2520. I should be able to reach 2400 fps @ 40,492 PSI or less if the gun-boolit strength-pressure-powder-lube combination is agreeable.

Accurate 2520 308 RCBS 173 grain 165-SIL in Savage 20.5" barrel
Charge / Velocity / PSI
39.0 grains / 2185 / 30288
40.0 grains / 2243 / 32791
41.0 grains / 2302 / 35474
42.0 grains / 2359 / 38353
42.7 grains / 2400 / 40492 ~ 90% case capacity

Boomer :Fire:

[Larry Gibson]

Boomer

Where are the velocity/pressure figures from using AA2520? I'd also suggest you test at 100 yards as you may find the accuracy is not quite as good as the 50 yard tests lead you to believe.

Larry Gibson

[runfiverun]

larry knows exactly where this was/is going.
that rifle&boolit is easily capable of 1" [consistent] 100 yd groups.
with that same boolit design and powder i get sd's of less than 10 in a 7mm.
but to lower your pressures a slower powder is required at some point.
you may not have nor get any leading. i haven't for a whole box of g/c's, with no cleaning.
but you probably have a nice grey wash in the bbl.
and are on the right track, so far, for what i think you wanna do.

[bdoyle]

Boomer,
Are these regular off the shelf RCBS moulds? I have quite a few RCBS and none cast any where close to being usefull unless the bore / throat is tight. The SIL moulds look like they might be worth picking up. I just bought a Savage 10FLP in 308 so this is real interesting.
Brian

[Boomer Mikey]

Boomer,
Are these regular off the shelf RCBS moulds? I have quite a few RCBS and none cast any where close to being usefull unless the bore / throat is tight. The SIL moulds look like they might be worth picking up. I just bought a Savage 10FLP in 308 so this is real interesting.
Brian

I got these two RCBS molds from Midway last month and they cast large enough for normal 30 cal use if you use an alloy with more tin for fill out. The 30-165-SIL has a 0.302" nose and 0.310" body using 50/50 WW/LINO or 75/25 WW/LINO and the 30-200-SIL nose tapers from 0.299" to 0.308" at the front of the lube groove and the body is 0.312".

I Beagled my old (1980's) 30-165-SIL mold this evening with a small aluminum tape strip on the bottom of the mold between the locating pins and I cast 10 pounds of bullets. The noses came out perfect at 0.3025" instead of the usual 0.301" and the small taper in the nose makes them easy to chamber with a comfortable "feel" to them. The body is just a hair less than 0.310"; seating gas checks and lubing the bullets in a 0.310" die they just barely kiss the die.

Boomer :Fire:

[Boomer Mikey]

I'm not one of those that agree with the RPM limit as an absolute, but I also don't believe in raining on your parade if you're fond of the idea.

This is a learning experience for me in that I'm willing to explore the possibility of consistent 2400 fps cast bullet loads; however, the 2400 loads should do what I started out to do just fine. What was unexpected is how relatively simple it was to get to this level... I didn't expect to get into the 2200 fps ballpark with 2400 and this bullet. I expected things to go away around 2000 fps.

If my tinkering doesn't work out you can say you told me so but I'm not going to throw in the towel just because the rifle has a 1:10 twist.

The velocity / pressure figures are Quickload's predictions for the RCBS 30-165-SIL seated to a COL of 2.7" and Accurate 2520 powder in a 20.5" barrel. Of the powders I have in the shop, 2520 predictions produced the lowest pressure to reach 2400 fps.

This is my first trip into the "Twilight Zone"........ :lovebooli

Boomer :Fire:

[Larry Gibson]

Boomer

Contrary to the notions expressed the RPM threshold is a "threshold" not a "limit". Those are two completely different words with different meanings and not a semantics play. I am the one who first espoused the RPM threshold concept on this forum (although the concept did not originate with me) and I have defined it numerous times in the RPM threads started by me. Each and every time I have clearly stated what it is. It is not a "limit". It is not an "absolute" with a set RPM figure. Each bullet/load will have it's own threshold where accuracy will deteriorate do to the adverse affects of RPM on the bullets flight.

It can be pushed with the right design of bullet and componants. Each different desgn will have its' own threshold. For most regular cast bullets the threshold is between 125,000 and 140,000 RPM. In your case you are taking some steps to negate unwanted obturation during accelleration. This is apparent in the steps you are taking of the fitting of the bullet nose in the bore. With such steps you will be able to push the threshold. However your goal with your listed 2520 loads of 2400 fps can be easily acheived velocity wise but you will most probably find accuracy disappointing. The accuracy at 2400 fps with that bullet most likely will not be near as good as it is at 1800-2000 fps. The reason is RPM.

Test at 100 yards instead of 50 yards. You will better see the affects of RPM more clearly there than at 50 yards. You have fallen into the beliefs of others who missunderstand the difference between a threshold (a threshold can be crossed or passed through) and a limit. Let me be emphatic one more time; the RPM threshold is not a "limit".

Larry Gibson

[Boomer Mikey]

larry knows exactly where this was/is going.
that rifle&boolit is easily capable of 1" [consistent] 100 yd groups.
with that same boolit design and powder i get sd's of less than 10 in a 7mm.
but to lower your pressures a slower powder is required at some point.
you may not have nor get any leading. i haven't for a whole box of g/c's, with no cleaning.
but you probably have a nice grey wash in the bbl.
and are on the right track, so far, for what i think you wanna do.

Do you have the same rifle in 7mm-08?

I had a hard time choosing between the two; I've been a 7mm-08 fan for quite some time.

This rifle was purchased for it's use as a cast bullet silhouette rifle and 30 caliber cast bullet mold selection was the reason for selecting it over the 7mm-08. 170's at 1950 fps will get the job done just fine. 2400 was selected for its ability to provide low sd's without using a filler. For this purpose, 2400 fps loads aren't desirable both from a fatigue standpoint and potential damage to targets for 200 meter silhouette. 500 meter silhouette is another story and the 200 grain cruse missiles may prove themselves worthy.

I'll replace the rear ghost ring with a Deluxe Target Fool Proof sight for open sight category shooting.

I have a longer stainless steel twin of this rifle in 7mm-08 that I special ordered and the RCBS 7mm-168-SIL mold... another project on the back burner.


Boomer :Fire:

[45 2.1]

This is a learning experience for me in that I'm willing to explore the possibility of consistent 2400 fps cast bullet loads; however, the 2400 loads should do what I started out to do just fine. What was unexpected is how relatively simple it was to get to this level... I didn't expect to get into the 2200 fps ballpark with 2400 and this bullet. I expected things to go away around 2000 fps. Boomer :Fire:


Glad to see your having an easy time. This is really the result of shooting a boolit that fits properly (that is has a nose that engraves and a body big enough for the throat. Larry could get the same results if he chose to shoot a boolit that had an engraving nose instead of the one he ran his tests with. His boolit comes with a 0.298" nose (maybe a hair bigger with the harder alloy he is useing) according to another tester of his mold. Out of plane bending/upset due to that undersize nose goes a long way explaining the so called RPM effect.

[Tiger]

Hallo all

Another thing to look too here in Boomers tests is the lube he chose. I've heard good things about this LBT lube and his test bear that out. Pay attention high velocity and rpm shooter.

Hallo Larry....good to see you again. Have you been on holidays too?<--Notice carpetman.

Ralf

[Larry Gibson]

Thank you for making my point 45 2.1 Although I doubt that was your intent.

As I stated; "This is apparent in the steps you are taking of the fitting of the bullet nose in the bore. With such steps you will be able to push the threshold."

A tight fitting nose on such bore riders usually results in a little higher threshold of RPM before accuracy deteriorates. However, with such steps all you are doing is raise the RPM threshold a bit. With the twist of Boomer's rifle he is going to lose accuracy long before he gets to 2400 fps. As he says he seems quite happy with the accuracy he is getting around 1950 fps. With the 10" twist of his rifle that is 140,400 RPM which at the top of the threshold. With the extra steps he is taking to ensure a tight fit that is where he should be for best accuracy with that bullet/load even though 2400 is a faster burning powder. He probably could push the RPM threshold a tudge farther by using a medium or slow burning powder but not by much. Boomer state's his reasons for using the load he has chosen and those reasons work for me. Hope he does well on the steel targets.

The 311291 that 45 2.1 is refering to actually runs .299-.300" when cast of linotype. That alloy was used in the last series of tests. That bullet with it's typical fit for a bore rider is conducive to answering the original question; why can't the average bullet caster when using such a regular cast bullet get accuracy out of his 10" twist rifle at velocities equal to jacketed bullets of equal weight? All of the tricks or the witchcraft often times recommended will not allow such a cast bullet to get the same accuracy at 2400-2500 fps as it does at 1800-1950 fps. The reason is RPM. The better fitting regular cast bullet might sustain accuracy at a higher RPM than an ill fitting bullet of the same design but it will still not provide the same level of accuracy at the high velcocity than it does at the lower velocity. If you work at it you can get consistant 3-3.5" ten shot groups at 2400+ fps with such regular ill fitting cast bullets. That however is not the same accuracy as 1.5" at 1900 fps or so with the same ten shots.

If one understands how the RPM threshold works then one can move on to better designed bullets and slower twists. I recently shot a 2" group that had 9 of the shots in 1.5". This was with the 14" twist Palma barrel using 311466 over 34 gr of 4895. Velocity was 2519 fps and the RPM was 129,600. At 2635 fps (135,600 RPM) the first 6 shots went into 1.88". At 2827 fps (145,500 RPM) the first 5 shots went into 2.75". Thus you can see accuracy at high velocity is quite possible and consistent if one keeps the RPM within the threshold. Even at high velocity it is obvious that the increased RPM is beginning to cause a corresponding decrease in accuracy. That bullet at 2 moa accuracy at 2650-2750 fps would be a 300 yard deer killer on any day.

BTW; Lube for the above bullet was Javelina and there was no leading.

Larry Gibson

[Larry Gibson]

Ralf

No, I've not been on holidays. I've been working on the east coast in North Carolina training Marines. It is a contract job that takes me away from home entirely too much. I retired from the Army last April but started this job when on leave in January of last year. This job takes me all over the country and up to Alaska (we train Army also). I usually have my laptop with me but with 14-16 hour days I don't have much computor time. It is satisfying work but I hope to be retired-retired next March. Until then my testing has been curtailed with my hunting also. I get some in such as continuing the RPM tests. but it is not going as fast as it would if I were home.

LBT is good lube but my previous tests have shown it to be no better than some other lubes. Bass was kind enough to send me a new stick of it so I'll see if something magic was added. I do hope it makes a difference at high velocity (2400+ fps in the .308). A thorough test will tell.

Larry Gibson

Added; I plan on testing the LBT and 2700+ lubes with the 311466 over 36, 38 and 40 gr of 4895. The velocity level should run from 2600+ fps to 2800+ fps. The bullets are already cast and are the same batch as with the above mentioned loads used with Javelina lube. The Javelina appears to be pooping out above the 2519 fps load. I will see if the other two lubes perform some sort of magic.

[Boomer Mikey]

Well,

I didn't get a chance to load or shoot any more over the last weekend but I did cast about 1000 bullets in two sessions with slightly different alloys.

I tried water quenching the stuff I have (range scrap + wheel weights) as cold as I could run the pot (about 700 degrees) with terrible results [undersized bullets].

I added 3 pounds of Lino to the mix and ran the temp up to 800 degrees and cast as fast as I could with good results. BHN 21 bullets the next day.

For the second batch I added 3 pounds of magnum lead shot and ran the pot between 800 - 850 degrees to produce excellent bullets as fast as I could run them. BHN 25 bullets the next day.

I'm a newbie to this 30 caliber stuff; I always ran my pot on the low side making 35 to 45 caliber nice and shiny bullets but this higher temperature process has busted my long time experience to pieces. The most remarkable thing about these bullets is their consistency in size and weight. over 90 % of the bullets weigh within 0.1 grain of each other. They aren't shiny with their uniformly frosted appearance and it's rather easy to empty a 20# pot in about two hours using two, two cavity molds... a 200-SIL mold and a 165-SIL mold.

I was under the impression the largest bullets were cast cooler due to lower shrinkage but it appears the largest bullets come from a hot mold that fills out better and hotter alloy flows better with fewer voids left in the bullets.

I spent the weekend moving my CNC mill into the shop through a 36" door and my back and hip are reminding me how stupidly stubborn I am.

I hope to resume shooting test loads this weekend at 100 yards.

Boomer :Fire:

[runfiverun]

mikey
i use the 308 and the 7x57 and 7x57 ackley.
the 7-08 is a twin to the 7x57 except that the powder "stacks" in a column a bit better for reduced loads in the narrower x57 case. plus the longer neck helps too.
and the steps you are taking do help immensely.
beagling--good idea, lube- check, trying it in the g/c groove? water dropping?
h/treating? filler ? fun,fun,fun...

[Boomer Mikey]

I went to the range Sunday to test loads at 100 yards. I spent the whole day Saturday sizing and lubing bullets… over 2000 RCBS 308-165-SIL and 308-200-SIL’s.

Testing at 100 yards was putting me to the test more so than the loads. I used a 10X AO Burris IER scope with target knobs I’ve had for well over 20 years mounted forward of the ejection port in Leupold QRW rings and it worked pretty well. Mirage didn’t help things and a couple of guys with a 300 win mag and an AR with muzzle breaks didn’t help matters.

No sub 1” groups but two groups less than 1.25” and several at 1.75” or less. The best group of the day was 25.5 grains of 2400 behind the 308-165-SIL for 2190 fps and a SD of 11.

RCBS 308-165-SIL 170 grains sized to 0.310” body; nose 0.3025”, lube LBT Blue soft, Case: WW, neck sized, match prepped. Primer: WLR, Powder: new lot of Alliant 2400. COL 2.73”

21.00 grains 1.22”
21.25 grains 1.2”
22.75 grains 1.6”
23.25 grains 1.6”
24.00 grains 1.7”
24.25 grains 1.5”
25.50 grains 1.18”

RCBS 308-200-SIL 205 grains sized to 0.310” body; nose factory taper, same case, lube, primer and powder. COL 2.85”

Best groups were between 21.0 grains and 22.0 grains ran 1.9” to 2”. Most groups averaged around 2.5 “, with the worst going 3” or less.
I want to give this another round of tests or two as by the time I started the 200 grain testing I had already gone through over 100 rounds and the guys next to me were hammering me with their muzzle breaks. I also discovered my front scope mount screw loose after I got home.

This rifle really likes the 165 at 2200 fps with 2400 and I’m going to bump up the charges next time until it tells me to stop.

Sweet spots: using 2400
165’s
21 – 21.5 grains
25 - 25.5 grains
200’s
18.5 – 19.5 grains
21 – 22 grains


Boomer :Fire:

[runfiverun]

well i think i am gnna have to get the flue tape out, for the 165.
and see what i get.
wonder how much 4831sc. will fit in a 308 case??

[rvpilot76]

Bump...any further updates? I just ordered my RCBS-308-200-SIL; should be here by Wednesday. Looking forward to testing it in my M1A.