Quickload help 7mm-08

[ClaynTexas]

Would anyone with quickload mind running 7mm-08 numbers?
I'm not really looking for top velocity in particular, but I would like a good idea of which powders would better suit my use for 7mm-08 in an AR. I'm thinking some of the powders often listed aren't suitable, such as H414, 4350, and the like.

Pertinent info:
20" bbl
85*F
860ft altitude
Win, Lapua, Prvi cases on hand, I don't know capacities.
WLR primers
120 TTSX
130 Speer BTSP
162 Amax

Other than that, I'm sure standard settings will work. I'm not looking for exact loadings, the rifle will tell me that. I'm just looking for powders and approximate charge ranges for the short barrel.

Thanks!

Almost forgot to mention powders I already have on hand from other projects:
RL15
RL17
PowerPro 2000MR
Varget
IMR 4895
8208 BR
IMR 4064
IMR 4166
Win 748

 

[Greyfox]

My 7mm08 AR is very accurate(.5moa), and cycles perfectly with 140gr Nosler/ Hornady bullets with 41-43gr of Varget. Sorry, I don't have Quick Load.

 

[frankinaustin]

Varget.

 

[MudRunner2005]

I use Varget in my 7mm-08 and .308 Win.

 

[HNDLDR]

First of all I'm sorry I don't have quick load either.
I also have an AR in 7mm-08 with a 20" barrel.
I hate to sound like a broken record but we use Varget in all four of our 7mm-08's.
I see you have IMR 4166 on your list. If you decide to load any of that in your AR I would love to see the results.
Sorry to distract from your post.

What brand/model is it?

 

[ClaynTexas]

No worries on the broken record. I figured the top picks would be Varget, RL15, 4895, or 4064. There's little info out there relating to 7mm-08 AR loadings.

I was interested to see velocity vs burn percentage in the 20" barrel. Certainly one or more of the top 5-10 powders will cycle well and be reasonably accurate. I would like to get a good idea of where the point of "too slow" is regarding burn rate. I don't want to buy powder I can't use.

The rifle is a Rem R25 that I picked up last year. I have put 5 boxes of Hornady Whitetail through it with somewhat mixed results. Probably 25-30 of 100 either short stroked or wouldn't lock bolt back when single loaded. No FTEs though. Roughly 15-20 percent of cases show brass flow into the ejector, yet normal looking primers. Also, ALL of the cases measured 2.040-2.045. I checked the last box before I fired them and they were also 2.040-2.045. I trashed the entire 100 cases. I've got other brands to work with.

 

[HNDLDR]

Mine is a R-25 also. 42 Grs of Varget under a 140 Nosler ballistic tip groups under an inch in mine. Velocity runs in the mid 2700 FPS range. Hope someone can find the answers you are looking for.

I've had poor results with all of the Hornady factory loads lately that I've tried including the ones you mentioned in 7mm-08. I also had poor results with their brand new brass in 25-06. (Inconsistent neck tension.)

 

[Greyfox]

My rifle is also an R25. The factory loads that I have used are Reminton 140 Accutips and Nosler Custom 140 BT's. I expect the timing of the R25 is set up for the Remington factory load. Both these factory loads produce sub MOA and feed perfectly. My 140 BT/Hornady SST's run 2700FPS with 42gr of Varget. I get loose prime pickets with 43gr of Varget. Varget burns well in the 20" tube and seems to have a compatable pressure curve for cycling the R25. This a the problem with some factory loads,particularly if you go to light bullets and incompatible powder burn rates.

 

[ClaynTexas]

Well I learned some things at the range today.

I had a quite a number of loads ready to try out (for about 3 months now actually) and I finally took a day off to do it. I had loads setup with Speer 130gr BTSP and IMR4064, IMR4166, RL17, and PowerPro 2000MR. I also had some setup with Hornady 162gr Amax's with the same 4 powders. I had ladder loaded from book minimum to book maximum with all of them. I had to interpolate for 4166 since I couldn't find exact data for what I was loading. I loaded 3 rounds of each powder weight increment and shot them as 3 shot groups.

The first thing of interest is that every single load, from starting load to max load, in all four powders using both bullets....flattened the primers. There was no cratering for most loads, only flattening. Only 4166 showed primer cratering at max loads. These were all loaded with WLR primers. I experienced the exact same thing with WSR primers in my 5.56 AR, but I knew beforehand that the WSR primers were soft. I haven't heard anything about WLRs being soft.

The second thing of interest is that all loads (from book min loads to book max loads) of IMR 4064 and IMR 4166 short stroked with both 130's and 162's. I tried different mags with no help. I didn't expect to see this. I thought 4064 would have been just the right speed for the rifle. There were no failures to extract or stovepipes, only short strokes. Accuracy with both was roughly 1" or a little better. For those interested, 4166 seems to show pressure signs way early.

The last thing of interest is that ALL loads (book min to book max) of RL17 and PowerPro 2000 functioned perfectly with both 130's and 162's. I expected both of these to be too slow to cycle effectively. Accuracy with both was roughly 1" or a little better, but with max loads the groups opened up a bit. At this point, I had run 120 rounds and it was probably much more me than the load or the rifle.

Next time I will try Varget, RL15, 748, and 4895. If what I saw today holds true, then 4895 should short stroke as well. I'm actually tempted to try Leverevolution or H380. I know some folks had had good results with Leverevolution in the 6.8 based wildcats.

 

[HNDLDR]

Clayntexas

Please keep the updates coming. I have the same rifle and a lot of the same questions about the shorter barrel.

 

[ClaynTexas]

Ok...
It looks like the first round of the ladder loads was all for naught. I was having trouble finding 7mm-08 brass and had picked a box of Lapua .308 (it was a steal at $59!) and necked them down. After loading, they all had consistent neck diameters of .314"-.315". Some of you see the answer already coming, don't you!

Since .315" is SAAMI max cartridge and .316" is SAAMI chamber minimum, I thought it would be fine. I dropped 1 loaded round in the chamber and made sure it would in fact chamber. It did.


Anyway, every load had flattened primers. Even the minimum loads. This made me think I had bumped the shoulder a bit too far when I loaded them, resulting in a bit excessive headspace. So I stripped the rifle and took the firing pin and ejector out of the bolt to try to see about this headspace issue.

I first tried one of the fired Lapua cases. It was a bit hard to get the bolt locked and definitely hard to get it unlocked. Next I tried one of the 10 cases I had left that were sized and primed, but haven't been loaded and are unfired. Same thing, hard to lock and unlock.

Next I removed the BCG and fed the same empty, sized but unfired case and and gave it a tap. I held the upper barrel upward and it didn't fall out. I gave it a smack and it still didn't fall out.

Next I put a once-fired and sized Hornady 7mm-08 case in and turned the upper barrel up. It fell right out. lightbulb
I also tried a new unfired empty PPU case as well as a factory loaded Hornady and factory loaded Remington. Both dropped right in and fell right out when flipped.

Next I chambered each of them with the BCG (firing pin removed) in place to see how hard/easy it would be to turn and lock the bolt. It was very easy with all except the Lapua .308 cases.

Long story short...It looks like my chamber neck is on the tight side and won't tolerate a necked down .308 without neck turning. I think this was causing excessive pressure and cycling issues across the board. So...it's time to try it all over again, but with native 7mm-08 cases.

 

[ClaynTexas]

It's been a while but....tried it all again and things worked out much better this time around. I used PPU 7mm-08 cases instead of necked down .308s. The only issue now is a bit of primer extrusion around the firing pin (cratering). It usually starts about mid-range in the loadings, but seems to be worse the faster the powder is. Interestingly, it didn't do it at all with Power Pro 2000. It seems to be tied to the burn rate of the powder and Power Pro 2000 was the slowest I tried. That aside, the primers are not flattening at all. They have nice round edges. I'm pretty darn certain it's not pressure, but an oversize firing pin hole in the bolt instead. Standard fare from AR308 style rifles as far as I can tell.

I fixed the short stroking issue. I ran about 100 rounds between handloads, Hornady Whitetail, and Rem Core-lokt. All ran flawlessly. The answer was the gas port. I took it apart and measured the gas port and it was 0.082". I opened it up to 0.093". The side effect, of course, is a bit deeper extractor marks on the cases. It might need a bit more carrier weight. If I could do it over again, I would try a #44 drill bit first and see if it was enough. Followed by a #43 if it wasn't.

I am going to give CCI #34 primers a day in court and see if that fixes the cratering issue. If not, supposedly JP Superbolt HP will fix it.

FWIW, I tried 4895, 748, H4895, 8208 xbr, 4064, RL 15, and PP2000 this time with 120 TTSX, 130 BTSP, and 162 Amax's. PP2000 gave best primer readings, H4895 gave smallest groups and worst cratering.

I will probably also try 139/140s and Varget next....just like everyone says to do. From what I've seen so far from the rifle, it will probably like those and the 162s best. It's decent with the 130s. It doesn't seem to favor the 120s, but I didn't fire many of them. Scope reticle snapped and I didn't take the spare with me.

 

[HNDLDR]

I was out of Varget so I ran some RL 19 through mine behind 140 and 160 accubonds. While they weren't as accurate as the Varget loads, they still hovered around one MOA and all cycled the action just fine. Sorry I didn't spend a whole lot of time working these loads up so I could share more information. I was busy enjoying a day at the range. That actually shot rather well considering they were just thrown together out of what components I had laying around.

 

[ClaynTexas]

I'm not surprised to be honest. It seems maybe they are ported for slower powder. Opening up the gas port to .093" seemed to fix that. I ran 4064, 4895, H4895, 748, 8208, RL15, and PP2000 and it cycled perfectly with all of them and always locked the bolt back. It seemed to group pretty well with H4895 and PP2000 at mid-range loads, 1/2"-3/4". I still need to try Varget and I need to pick up some #34 primers. I would like to eliminate the primer cratering issue. I did have one pierce at max load with RL15 pushing a 130 BTSP. It's definitely not too much pressure, just an oversize firing pin hole.

Thanks much for the input you have given me.