honandy sst

[stillquietvoice]

i just bought 200 7mm 139 gr hornandy sst bullets for my 7mm08. has any one loaded for them yet. how accurate have they been for you and with wich powder. i currently have imr 4350,4895 and win760. wich would yield the tightest groups. im loafing for rrm 700 sps sa 24" sport barrel. longest range i have accrss to is 400 yds.

[T. O'Heir]

You must work up the load for your rifle.
I'd start with the 760. Gives the highest velocities with Start loads.

[stillquietvoice]

thank you ill syart there and give tange teport.

[firewrench044]

I use 150gr SST's in my 308, 3006 and 8MM Mauser for hunting
When zeroing scope they made the hole in paper larger at 100
and at 200 all holes are touching
Last year, 3 dear just dropped the fourth ran 100 yards to a irrigation
pond where a gator grabbed her, I guess my aim was off after a long
bad day ( everything went wrong )

[qrz]

The ballistics for a 7-08 are really fun. My rifle is 1:9.5 twist and likes a heavier bullet. Your win760 and imr4350 are both good powders and recommended by Hornady 9th p330. If you have a slower twist the 139-ers might be the ticket for you. Will be interesting to hear how the 139-ers perform.
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Lyman 49th p190 has the imr4895 as their best performer but a different 139 type bullet w/ a much lower bc so who knows.
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You won't know what is best as all chambers are not equal.
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Speer #14 p351: Some 7-08 rifles have short throats. Caution when seating bullets to contact the rifling. Industry standard for this cartridge is 52K cup and should not be exceeded.
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Have fun....

[stillquietvoice]

just loaded up a box using w760 have to do some more for a range session sunday.
i am loading from the magazine so coal is limited to what will fit. longest i can go is 2.805" the throat is closer to 2.9" so i wont have overpressure from jamming into lands. have to adjust using powder charge...

[ammo.crafter]

The 139gr in my singe shot 7x30 Waters firing 5-shots are covered by a dime consistently at 100yds.

HODGDON CHARGE 30 TYPE H322
HORNADY WEIGHT 139 TYPE BT SST

[stillquietvoice]

thats great shooting thanks for the info. tells me that they are capable of great accuracy.

[Unclenick]

Stilquietvoice,

Winchester 760 and Hodgdon H414 (same powder in different brands) is a canister grade version of WC760, one of the Western Cannon series of powders from the St. Marks, Florida powder plant. In 1989 CCI reformulated their magnum primers specifically for improved ignition through the heavy deterrent coatings on that series of powders and similar formulations. You may find you get better accuracy and lower velocity spread with those primers with that kind of powder. Because magnum primers can sometimes (not always; it's complicated) raise pressure a bit, I recommend you back your load down about 5% and work back up to best accuracy.

This system is one method of finding best accuracy loads.

Best accuracy depends, among other things, on getting barrel time right, and different powder characteristics and bullet weight combinations produce different barrel times, even when they are producing the same final muzzle velocity. In general, a slower powder produces a longer barrel time than a load using faster powder to produce the same velocity. The slower powder will reach a lower peak pressure, but produce more gas to have a higher muzzle pressure. Matching velocity depends only on the average pressure being the same, so the higher muzzle pressure and lower peak produce the same average in this instance. To produce that higher muzzle pressure the slower powder will generally require a charge weight that makes more total gas and higher muzzle pressure, both of which contribute additional recoil.

For a given size case, the smaller the bullet it is necked down for, the smaller the total expansion ratio, so the more confined the powder is. This means that the smaller the bullet the slower the powder needs to be to give the bullet time to get far enough forward so the total space the powder burns in is large enough to peak at the right pressure value.

Your 139 grain bullet has the same sectional density as a .308 bullet that is 163.5 grains. However, its diameter is about 8% smaller. If we divide 163.5 grains by 0.92 (8% less than 1) we get 177.7 grains. So I think you'll find powder charges for 178 grain bullets in the 308 Winchester tend to give similar peak pressure to the 139 grain 7mm-08, assuming similar construction and seating to leave similar powder space. Velocity of the lighter 7mm will be higher, though. It's not an exact way to figure it, but is close enough to give you lists of potential powders from 308 Win data.

[RC20]

They are pretty damned accurate bullets

[stillquietvoice]

i have a speer #11 loads listed are considerably higher with magnum primers than hodgens web sight lists. the 308 175 listing for 760. is higher than listed weight for 139 7mm. if i understand you correctly. then the start load of the 308 should be close to an accuracy node.

[MJFlores]

I use 45 cal 250 grain SST's in my Muzzle loader and they deliver outstanding accuracy. I just started shooting 165 grain 32 cal FTX's which I believe are the same thing as SST only with a softer tip intended for tubular magazines. They are also quite accurate from what I've seen so far. I've only heard good reports on game too.

[Unclenick]

Originally Posted by stillquietvoice

if i understand you correctly. then the start load of the 308 should be close to an accuracy node.

The start load is not necessarily on a precision (smallest group size) node. My estimate just gives you another resource for looking for suitable candidate powders in an appropriate burn rate range. The OCW load development site I linked to is about a concept Dan Newberry has for finding loads that do well over a range of barrel lengths and chamber sizes. Those are the exception, though. For other loads you sometimes can take two identical rifles off the rack at the store and, due to tolerances, find they are different enough that they don't tune some bullets to best precision with the same charge weight of the same powder. So best precision and accuracy (where the group is centered; the result of your sight settings) have to be tested for. Also, be aware there are other things than charge weight that affect these. Seating depth is one. Cartridge concentricity is another. Priming technique, if done badly, can affect it adversely. So there's no simple guarantee some other person's load will shoot well in your gun. You have to do the work to see what it likes.

Originally Posted by stillquietvoice

i have a speer #11 loads listed are considerably higher with magnum primers than hodgens web sight lists. the 308 175 listing for 760. is higher than listed weight for 139 7mm.

The Speer #11 was published in 1991. That's from back when many bullet makers did load development entirely by pressure signs and without pressure testing other than making estimates from brass and primer deformation, a practice that can be off by up to 50%. Since then, both powder manufacturing processes and primer formulations have changed. Pressure testing of maximum loads is now done by everyone, I think, for liability reasons. That 25 year old data is too old to be considered valid without retesting and careful workup. Some of it will be OK, but some will be obsolete.

In my Speer #14, the loads for 760 in 7mm-08 are the same for their 130 and 145 grains bullets (they don't make a 139 currently) and the load for the 168 grain 308 Winchester bullet are all the same; 45-49 grains of 760 over a CCI 250 primer. They don't make a 175 or 178, but their 180 grain load data is only 1 grain less (44-48 grains), so I think my estimate is still well inside the ballpark, as 1 grain is about 2% of the maximum charge, which is just one step in a pressure work up. If your #11 data is higher than that, you can expect it was worked up in a production gun without pressure testing, and that may well account for the difference. If so, it should be considered obsolete.

The Hodgdon data for a .308 with 175 grain bullet is 46-49 grains, so that's another validation of the estimate, to my mind. The only thing that's off is Hodgdon's 7mm-08 load, which is an unusually narrow 45.5 to 47 grains, with the top load pressure being just 44,100 CUP average, when the 7mm-08 is rated for 52,000 CUP average. So they seem to have stopped low for a reason. I'm going to hazard a guess that the fact they used a standard primer gave them a high pressure spread so they erred extra low with the maximum. You could call and ask them, but when they stay that far below the SAAMI standard maximum it is usually for a reason that came up during testing. It may or may not apply to your loads if you use the 250 primer.

[stillquietvoice]

my #11 speer manual ismost likely a third printing sept of 1988 i bought it new to supplement my #10. i check it mainly as a comparison of online data. i appreciate the information youve given both on this subject and other topics. just eanted to make sure i understood what you were saying.
you are correct that speer 11 used production rifles for data testing for the 7-08 a rem 700 24" was listed as their test gun.
i went out to range today and ran my first test with 760 standard primers. loaded consecutive from 45.5-47.0 in .1 increments. will get some mag primers and start again. i have 2 other suitable powders to try on hand that dont require mag primers.
there is a great deal of satisfaction that comes from producing ammunition that performs well.
shooting your own loads is only half the fun.

[Jim243]

I can't speak to the 7 mm's, This is with 130 Grain SST's in 270 using H-4895 and standard Win LR primers. This is actually 5 rounds into the target.

Good luck and stay safe.
Jim

[Sure Shot Mc Gee]

As read your a fellow who seats his bullets up against the barrels rifling hoping to see his barrels best accuracy. There is a typical power reduction formula used in those circumstances. As I recall I think its 15%_? And too. Powder selection for that type of shooting is Oh so very important.

Firearm:
A (stock-700) {carbon steel} tapered sport barreled 7mm-08_? You needant wouldn't worry to much about the pressure development situation as most barrels are proofed. You need to worried about your barrels rifling erosion though.

Just S/S thoughts is all.

[Ifishsum]

SSTs are very accurate bullets IMO, and also very tolerant of jump into the rifling. I've only developed one load so far for my 7mm-08, with Varget and loaded to magazine length; it's a hunting rifle and I fire it only occasionally so I basically used the first MOA or better load I found which happened quickly.

[e-bear]

Jim243, thats some very nice shooting for a 5 shot group. If you don't mind would you tell me how many grains of 4895 are you using?

[HiBC]

If you look at the previous posts,they were written in 2016.

I would not expect an answer from the OP after 6 + years.

[e-bear]

HiBC, I am quite aware of the time frame here but ya never know. Jim243 just might happen to see it and say "WOW!" and send me a response.....

[Mal H]

If you check Jim243's profile, you'll see that he hasn't visited the forum since July, 2016.

[Savagehawg]

I use IMR 4350 behind 150 grn partitions in my 7mm-08 and get .333 groups at a 100 yards, never tried the SST's in it but i used to use them in my 25-06 and could get them all touching at a 100 yards

[Unclenick]

Zombie thread. It would get more answers and input to start a new thread on the topic.

Thread closed.