Any (7mm-08 / H414 [or 760] / 139SST) 1st hand experience?

[jimbires]

use a fired case . do not resize it . weigh the empty case . slowly fill it to the top with water . keep the water flat , no bubble on top . if you get a bubble , or drippers on the side of the case just touch it with a paper towel . I use an infant medicine dropper . weigh it full . the difference is the water capacity .

 

[308win]

Full case - empty case = case capacity.
Do this for 5 cases to get an average

 

[honestern]

I recently got a B&C stock to drop my Savage 7mm-08 sporter into and saw undeveloped handloads move from over 1.5" at 100 to well under an inch (.7-.8ish). Very encouraged with the improvements so now I've begun some true load development for this setup. FYI - always looking to learn more but I'm a very experienced reloader and have experience with reading cases/bolt lift for pressure signs.

I built a ladder charge using the 139 SST's I had on hand (.486 G1 BC) and H414 which I have a good deal of (I know, not ideal for temp stability but has never given me issues personally) ...

I used data from Hornady 11th edition (mobile app) which shows max charge of 49.9g. @ 2900fps

• Hornady FL sized, trimmed, weight sorted all cases weighing within .2gr of one another
• CCI-BR2 primer
• Savage 10
• Savage factory sporter 22" barrel (do not know the twist rate)
• Sunshine, slight breeze, 45 deg F - firing from bench in shade under the roof over the firing line

I started at 46.7 and moved up in increments of .3g. The top 3 or 4 charge weights were definitely compressed some.

I started at the bottom and the chronograph clocked the 46.7, 47.0, 47.3, 47.6, & 47.9g loads between 3000-3050fps. - I wasn't expecting any pressure signs down here since I was starting out a good bit below max (6.5%) but I was NOT expecting velocities near that high. The Hornady 11th ed shows 47 grains should put the velocity somewhere around 2750 fps (with a 24" bbl while mine is just a 22"bbl)

I had loaded the ladder to book max (49.9g according to Hornady 11th) plus a couple more (last/highest at 50.6g), planning to stop when an ejector mark arrived at the party ... No stiff bolt, no marks, no primer craters, etc so I continued and saw velocities increasing all the way to 3180-3208 for the final 3. My final load of 50.6 (.7g above hornady published max) finally showed an ejector mark (3208fps).

Not really looking for information on which different bullet or powder or cartrige, etc that I should be using, but specifically I am looking for:

• Have you ever loaded 139g SST's over H414 for a 7mm-08 and if so - what kind of velocities did you get? EDIT: Or Win760
• Have you loaded a different bullet (especially 139/140s) over H414 for a 7mm-08 and if so, did you see velocities exceeding expectations significantly?
• If you have QuickLoad - what does the software say I "should be getting" and where I "should" be stopping on charge weight?

BTW ... I am using a Caldwall chronograph I purchased used from another member here and have only recently begun to use it ... it is NOT a known quantity for me yet but I have chrono'd a number of rounds from a few different rifles and have not been getting values that would make me think the Chrono is off by 200-300 fps which is about the "surprise" delta I am seeing with my above load combo ...

Would love to hear your personal experiences with H414 in 7mm-08 and/or QuickLoad data ...

Oh ... and if it turns out this data is not too good to be true and is safe and accurate, I think I'll name this rifle "The Unicorn"

Thanks

I have been loading for 2 rifles chambered in 7-08 for 20 plus years. Both with 22" barrels, Savage model 11 and Remington 700. I have been loading H414 in both with Hornady 139 BTSP's and Federal 200 primers. 46.0 grains in the Savage and 47.0 grains in the Remington. The Savage chrono's at 2852 and the Remington at 2895 . Both rifle shoot between .5 and .75" at 100 yards. I wouldn't push these much more than 47.0 grains. These rifles have accounted for 5 elk and 1 mule deer. All have been one shot kills except for one elk that kept going after it was hit in both lungs. All of these kills have been kills by my daughter, a nephew and a friends daughter. The 7-08 has low recoil and kills very well.

 

[nkyshooter]

@jimbires & @308win - finally was able to get the water capacity today - my fired/unsized hornady cases with spent primer all weighed exactly 166.1 (I had weight sorted them before loading) ... with water to the mouth of the case, they were 222.1g ... I calculate this to be 56.0g exactly of H20 capacity ... I see Jim's QL output shows a "usable" h2o capacity of just of 47g ... is the "usable" measured to the mouth of the case? ... or merely to the neck/shoulder junction or somewhere else?

What say QuickLoad with this water weight?

Also - do I understand correctly that there can be variation by as much as +/-10% (for total potential delta of 20%) between powder lots? And - if this is correct, AND IF my lot happens to be on the slower end, then the weights prior to encountering pressure should therefore be a bit higher?

I am leaning more and more towards the chrono being off and I plan to re-run my ladder - this time using the same cases but neck sized only - over a different chronograph as soon as I have the chance. If I can set up both the one I have as well as another in serial, I hope to get either validation or correction on what mine has been telling me.

 

[Orange Dust]

I used to shoot 50grs of W760 in mine with the 139SST. WW cases and Mag primer. Velocity was 3024 in a factory 700. Pressures were fine and had good case life. W760 is pretty much like using H414 with a different lot number. Every barrel is different though, and normally velocity is a good indication of pressure. I would check the load with another chrono. My old Remington had a very long throat.

 

[nkyshooter]

I used to shoot 50grs of W760 in mine with the 139SST. WW cases and Mag primer. Velocity was 3024 in a factory 700. Pressures were fine and had good case life. W760 is pretty much like using H414 with a different lot number. Every barrel is different though, and normally velocity is a good indication of pressure. I would check the load with another chrono. My old Remington had a very long throat.

Thanks Orange Dust - what was the bbl length on that 700?

 

[308win]

@nkyshooter Do you have the temp for the day you were shooting and also the velocity with each powder charge? I'm showing at your 47.9gr load to be well within pressure limits and running around 2865fps. Different neck tensions and different barrels will give different results so the more info you can give the better the output will be.

 

[308win]

Using your 50.6gr load and 3208fps that would give you a 106.3% case capacity and 87653psi!!! Max on the 7-08 is 60191, so I'm guessing you would have seen a little bit more than an ejector mark at the pressure. Going with the standard burn rate of H414 and 50.6gr of powder, your estimated pressure would still be in excess @ 69188psi. Either way, to hot of a load. Using the standard burn rate, your max load would be 48.6gr @ 70° estimated at 2909fps. Estimated OBT Node for your 22 inch barrel would be 46.6gr and 2782fps. Hope this helps and remember these are all estimates based on your given information.

 

[nkyshooter]

@308win - here is more info ...

Naturally, with this development going on at 45F, I don't want to end up settling on "too high" a charge weight on the outside chance I do fire it in summer weather ... 47.6-48.5g looks REALLY good - except for that funky anomaly at 47.9. Disregarding that (and assuming my chrono has not soiled the bed) I have an ES of 19 on a charge window of about 1g - that would be AWESOME if it is truly accurate.


Neck tension was using a Lee FL sizing die (not my normal approach after finding my load as I typically use a Lee collet - but this is my only current option for FL sizing 7mm-08 at this point). I seated with a Frankford Arsenal Universal Micrometer Adjust seating die using the medium stem. I set the COAL by first using a stoney point guage with a factory modified case (not homemade) to get my COAL at the lands of about 2.860' ... seating to the cannelure put me at approx 2.795" COAL tip to base - I did not use a comparator.

I used a Lee Factory Crimp die to just put a very light crimp on them for added consistency.

BTW - prior to priming with the BR2's, I used the Frankford Arsenal Case Prep Center and trimmed all to hornady published "Trim Length" then weight sorted and then sorted out 15 of the heaviest I could that would all be within .2g of one another ... my h2o measurement validates for me that I have very consistent internal volume in the cases I used for this ladder test.

Temp at time of firing was approximately 45F - I was fully shaded and so was the chrono ... chrono was set up with sun shades but was close enough to rifle that the muzzle blast blew off the sunshades about half way through or so ... Roughly 2-3 feet from muzzle or so? ...

My record is below - let me know what else I can tell you that will be of assistance?

	Charge wt	Velocity	Observations/Notes
1	46.7	2858	False reading? 1st shot on cold barrel ...
2	47.0	3022
3	47.3	3033
4	47.6	3045
5	47.9	3092	Oddly higher than next 2?
6	48.2	3061
7	48.5	3064
8	48.8	3105
9	49.1	3118
10	49.4	3134
11	49.7	3168
12	50.0	3192
13	50.3	3180
14	50.6	3208	clear shiny ejector plunger circle

 

[nkyshooter]

Using your 50.6gr load and 3208fps that would give you a 106.3% case capacity and 87653psi!!! Max on the 7-08 is 60191, so I'm guessing you would have seen a little bit more than an ejector mark at the pressure. Going with the standard burn rate of H414 and 50.6gr of powder, your estimated pressure would still be in excess @ 69188psi. Either way, to hot of a load. Using the standard burn rate, your max load would be 48.6gr @ 70° estimated at 2909fps. Estimated OBT Node for your 22 inch barrel would be 46.6gr and 2782fps. Hope this helps and remember these are all estimates based on your given information.

We 100% agree the 50.6 was too hot - I got a very clear very shiny perfect circle on the ejector ... that was my first sign of pressure and fortunately was also the last/highest I had loaded for the test.

Forgetting about the velocities for the moment since there is valid question on its accuracy - my gut feel (based on a LOT of reloading at this point) is that around 50 give or take is the max in my rifle (Hornady 11th ed says 49.9g is max).

If my velocities are wrong BUT wrong "consistently" - I have a very good node in the 47.5-48.5 charge weight which "should" be a nice full capacity yet not too hot a load with some pressure margin of error if shooting in another 40-50 deg F warmer ...

I'll be interested to see what QL says with 56.0g as the h2o capacity - @jimbires 1st QL results showed the "usable" capacity for the "default" case was just over 47g h2o but I don't know the definition of "usable" ... is that to the mouth? ... or to the neck/shoulder? ... My h2o weights were to the mouth.

BTW - in the FL sized cases during the ladder - I was compressing a bit and in increasing amounts of course beginning around 49.5 or even just under using a 2.795 COAL.

 

[308win]

@45° I'm now showing max load to be 49.3gr estimated at 2912fps. OBT Node @47.3gr and 2784fps

 

[308win]

This was entered using your 56gr water weight

 

[nkyshooter]

If my particular lot o 414 is a bit slower than the "defalut"/"normal" ... wouldn't that allow me a tad more powder before pressures and therefore potentially a bit more velocity as well?

Out of curiosity - if the lot to lot variance can be as much as +/- 10%, I wonder what QL would say if my lot is 5% slower than "norm" ... and at 10% slower than "norm" ...

I may have to break down and buy a license - I"m finally to the point that I understand enough to "need" it at this point ...

 

[308win]

Short of it is, I don't believe you have a unicorn. I think its time for a different chrono, good luck