Questions Regarding a SA700 and the limitations therein

[hseII]

I've got a Remington 700LH SA that is currently a VSF.
I plan to have my smith install a new barrel after lapping the lugs and Truing the action.

I'm want to go with some sort of 6.5mm in 139-142 grain.
I will be hand loading.

My Smith is willing to do whatever I want, and he is good.

My Requirements are as follows:
1) Depenable
2) Accurate
3) Reasonable Component life- <1500 rnds is less than ideal.

Which gets me to my question:
What is the max length a SA will cycle a round?

I understand that if AI type mags are used, 2.890" is the ceiling: but Wyatt blind mags are good for 3.00"+/-.

But how long will the action accept?

Has anyone tried mating a LA magazine to a SA gun?

Does the 260AI need the extra room to run the 140s optimally , and if not, what length is desired?

I understand some are using a LA for the 260 in different forms, but is that necessary to leave nothing on the table, so to speak, with the 260(s)?

Is 2900fps +/- 50 attainable with a 26" not 5r top quality barrel, 140 grain projectiles, and an AI length loading?, or am I wanting the whole cake, without the sugar high?

Am I understanding correctly that the 140 class pills from Berger, Sierra, Lapua, and seem to group best in the 2850-2950fps range?

And as far as what I want to do with it, I want to shoot long and accurate, from a table, from prone, and in the field. Middle of the road on weight, best of both worlds if possible, and a suppressor will be tested with it also.
Deer at 600 yrds, and targets at 1100yrds.


Thank You

 

[benchracer]

Though I personally have a 700 LH SA, I can't be of help on your max OAL questions because I have never hesitated to load long and single feed where I felt that was necessary.

As for your 6.5 choice, I believe you should seriously consider the 6.5 SAUM. It will give you enough case capacity to use slower, cooler burning powders that can still deliver excellent velocity at less than full throttle, which also extends barrel life.

Go with the 6.5 SAUM and have your barrel melonite treated for a long accuracy life.

 

[abishai]

I have 260 rem and a 243 that I load to mag feed (both short action) . One uses AICS mags , the other uses wyats . In my 260 I run WAY too much H4831sc and 140 hybrids. I still have room to run more , and I am 3 grains over max . You will need to inside neck turn and also use a bullet that likes to be out of the lands ( hybrid, Amax, SMK are a few )

 

[jonbearman]

I would think the .260 or 6.5x47 lapua would be a good choice to 600 yards. If you seat long and they still fit in the mag you might have to pull the bolt to unload a round but should eject emptys fine. I built a .260 but my choice was a long action. The 6.5 saum would be interesting but wouldn't it be more overbore using more powder. However the 6.5x284 would be a good choice but barrel life would be short unless you get it melonited, that could extend it to a better life.

 

[benchracer]

The 6.5 SAUM has shown the ability to push 140's well in excess of 3000 fps while maintaining an accurate barrel life north of 2,500 rounds. Trying to understand its performance by comparing it to the 6.5-284 will lead one astray.


http://www.longrangehunting.com/forums/f19/6-5-saum-101316/

 

[XTR]

The 6.5 SAUM has shown the ability to push 140's well in excess of 3000 fps while maintaining an accurate barrel life north of 2,500 rounds. Trying to understand its performance by comparing it to the 6.5-284 will lead one astray.


http://www.longrangehunting.com/forums/f19/6-5-saum-101316/

You are going to have to explain the magic to me that makes a 6.5 SAUM less of a barrel burner than a 6.5x284. Just because George Garner had one that lasted is not a trend. Danny Biggs set the F-Open National Record with a 7RSAUM barrel that had 1700 rounds on it (at least that is what he told me a few yrs ago), but I think you'd be hard pressed to find someone going to the line at a National with a barrel that has much over 1000.

Build a 260 or a 6.5x47L.

 

[benchracer]

If you bother to read what is out there, the explanation is clearly made. Others are doing the same thing George has done, with the same results. Believe what you wish.

 

[Drop Port]

"I understand that if AI type mags are used, 2.890" is the ceiling: but Wyatt blind mags are good for 3.00"+/-."

AI mags from Accurate Mag have no front plate and have an internal of approx. 2.980"

You need to mock up a dummy round with a bullet optimally seated and go from there. A 6.5x47L will fit a standard mag box even with a 140 seated as long as desired.

 

[hseII]

"AI mags from Accurate Mag have no front plate and have an internal of approx. 2.980" "

I called BO last week and they told me the number above: if there is more room, that would be great.

I'd like to stay with the Short Action if possible.

How is there any better barrel life with the SAUM than the 6.5x284? Similar Pressures, Simular Velocity: what would cause longer Barrel life?

Is Anyone shooting the 260AI in a SA with detach mags?
If so, what length are you running, what velocities, and which projectiles?

 

[hseII]

Also,

We are searching for the right barrel now: the VSF is currently throwing 55grain BT around 3600-3700fps and boringly, I might add.

 

[flatlander]

I built myself a 260 Improved 30* on a SA 700 a couple of years ago, and have been shooting practical/tactical steel target matches with it, running all rounds through AICS magazines. My bbl is a Krieger 1-8.5tw, 26" long, and I'm able to get 2820fps out of any & all the 139-142gr class of bullets that I've tried, using IMR4350 or their new 4451 powder. I don't know whether I could reach 2900fps with this case or not, but am getting fine accuracy right where I'm at, and since any of the Berger 140s I'm using (LRBT,Hybrid,VLD) will remain supersonic out past 1400yds when started at or around 2800fps, I'm not going to push it. I form my cases out of WW243 or WW7-08 brass - just try finding any of either right now, and you might begin to understand why I'm not motivated to push my loads until primer pockets are ruined. What's most important to me is that Berger 140 Hybrids or VLDs shoot great at 2800fps, even when jumped a bunch when loaded to magazine length in the 260 Imp. If you really need a little extra length, try Accurate Mag AICS-style magazines w/o the binder plate in the front of the mag body. They won't be as rigid/durable as the same mag with the binder plate, but you can seat bullets out a few thou farther.

Just finished load development with a 6.5x47 Lapua in a rifle built around a Bighorn TL2-SA, which uses the same AICS mags as the SA 700. IMR 4451 is giving me 2795-2800fps with the same Berger 140s used in the 260 Imp, but in the shorter Lapua case, I'm able to seat these bullets out to the point where the bearing surface/boattail junction is right at the base of the neck, so they're not impinging on case capacity. Accuracy at 1000yds is very good, so again, I'm not motivated to push the limits trying to get another 50fps out of the 140s.

I know George has talked about getting longer bbl life out of cartridges he's used in his rifles by going with a case big enough to get reasonable velocities out of slow powders like H1000 or N165. N160 & N165 have the lowest flame temperatures of powders with comparable burn rates according to Quick Load; I think it's logical to expect lower temps to be less hard on throats, but at the same time, doubt it's going to make a huge difference. H4350 is known to be hard on bbl throats, especially in a 243 or 6.5x284, yet look at how many shooters are still using it. Pick your poison - bbl life is going to suffer when you go to a case with larger capacity for a given bore dia, no matter which powder you use.

 

[hseII]

"I built myself a 260 Improved 30* on a SA 700 a couple of years ago, and have been shooting practical/tactical steel target matches with it, running all rounds through AICS magazines. My bbl is a Krieger 1-8.5tw, 26" long, and I'm able to get 2820fps out of any & all the 139-142gr class of bullets that I've tried, using IMR4350 or their new 4451 powder. I don't know whether I could reach 2900fps with this case or not, but am getting fine accuracy right where I'm at, and since any of the Berger 140s I'm using (LRBT,Hybrid,VLD) will remain supersonic out past 1400yds when started at or around 2800fps, I'm not going to push it. What's most important to me is that Berger 140 Hybrids or VLDs shoot great at 2800fps, even when jumped a bunch when loaded to magazine length in the 260 Imp. If you really need a little extra length, try Accurate Mag AICS-style magazines w/o the binder plate in the front of the mag body. They won't be as rigid/durable as the same mag with the binder plate, but you can seat bullets out a few thou farther."

Golden Information, thank You Sir.

What kind of accuracy are you experiencing with that setup?

 

[rifleman700]

Without hesitation 6.5X47L. I also shoot 6.5-4S, 6.5CM, .264W and the Lapua is my favorite.

 

[flatlander]

Both 6.5x47 & 260 Imp 30* rifles shoot little bughole groups at 100yds when checking scope zero, and with their favorite loads, will hold 2.5"-3" 5-shot groups at 600. Just finished 'training' one of the ballistics apps on my phone a couple of evenings ago with the 6.5x47, finishing up by shooting Berger 140 LRBTs at 1000yds. Three of five shots were in a little cluster that measured under 1" of vertical and 3.5" horizontal spread. 1st shot was a miss just over the steel IPSC target, and the last round hit 8.2" low out of the group. Nothing to brag about when you're talking to a 1000yd BR shooter, but there's potential there.

 

[TC260]

You are going to have to explain the magic to me that makes a 6.5 SAUM less of a barrel burner than a 6.5x284.

I don't follow these "controversies" or regularly follow those other boards but when I was doing some research on cartridge choices I looked into some of these long barrel life stories and from what I recall it basically boiled down to the definition of barrel life. x000 rnds from a 6.5 SAUM for example included setting the barrel back several times along the way. Generally people seem to refer to barrel life as how many rnds till the barrel needs to be set back (if it can be). So at least from what I could tell that's the source of the huge discrepancy in barrel life numbers.

 

[mysticplayer]

Accurate bore life - love that statement cause it all depends on your needs and what you define as accurate.

I keep an eye on tales of extended bore life cause as an F class shooter, I eat barrels so anything to help is great for the wallet.

What I see as a trend, is the stories of long barrel life usually are tied to precision rifle or hunting. Now I am not saying these guns are not accurate. What I am saying is the LEVEL of accuracy they call accurate is different.

Whatever this means to you, I suggest doing a simple test. When your barrel is new on a nice calm cool morning with its best loads, your best rests and karma strong, put up 1 target with 5 aiming points. Do whatever warm up you want to get in the groove and then shoot 5 5rds groups on that 1 target.

Use flags, spotters, voodoo dolls... whatever. Just take your time and make each shot your best. This defines the baseline of the barrel.

Now enjoy the rifle and some time in the future (1000rds or so) repeat. No "pulled" shots or excuses. Same deliberate, best conditions shooting.

Compare the average groups... I bet you see a change and it will be significant.

With a properly built modern rifle using top match barrels, I bet you can reach the 2's and 3's with most any chambering and match bullet. Next time you test, the average is now in the high 4's and likely in the 6's. Still very accurate BUT that is a huge percentage change in accuracy.

For the PRS shooting, around 1/2 min accuracy is going to be smoking accurate. For an attempt to podium at the US Nationals in F class at 1000yds, not a hope.

For a SR BR shooter, wouldn't even bother wasting the powder or bullets to test as the barrel never left the gate.

So who is right, who is wrong? No one. Shoot to the level of accuracy that is needed to complete the task... change barrels when necessary.

I compete in FTR with the 308. Do any reasearch and you will get lifespans that might reach 5 figures for "accurate" life.

I took that advice and figured, barrel has mid teens... no problem. At 1000yds, that X ring gets really really small. There was an obvious tall off in accuracy for my needs when I approached 2K rd counts during the match. That's frustrating.

For me, I will never take a barrel into a big match where I will END with more then 1800rds..... better if it ends under 1000rds.

To podium at 1k at a big US match, I need to have a rig that will group inside that X ring (5" circle) so it better hold sub 5" groups over 22rds or more under ideal conditions ( I make enough mistakes for the rifle ). Unfortunately, that level of performance is fleeting in a bores life.

For a tactical shooter using the 308, I doubt he will even consider the barrel broken in when I take mine off....

YMMV.

Jerry

 

[bsumoba]

Let me first say that I understand where you are coming from. I was in the same boat. I come to realization that there are no free lunches here.

IMO, the 6.5mm bullet works well anywhere from 2650-3100fps and you could go through the whole list of cartridges to fill in that will meet this criteria.

I know MANY guys that will not take a barrel with more than 800-1000 rounds through it to a national event (F-Open). These guys are using 284 Shehane's, 7 SAUMs, 6.5x284, etc. Reason being, you don't want to be there during a relay when all of a sudden your barrel takes a dive. Their argument (and now, ultimately my argument as their logic makes sense to me, is that a barrel with less than 800-900 down the tube will probably be safe from this phenomenon. Local matches are a different story. I will probably use my 284 Shehane until it actually degrades in accuracy and/or my X count starts taking a dive and that could be 2K, maybe even more....hopefully. Then, it will be relinquished to fireforming duties.

You got to also take into account how fast you are shooting. You can get a barrel with a known barrel burner cartridge to shoot well for a long time if you shoot say 1 shot every 2-5 minutes. : Me being a F-Open shooter, I can sometimes put 15 rounds downrange in a matter of a few minutes. Likewise, you can take the 260rem and blow off a couple 10 round mags one after the other and toast it and greatly reduce its barrel life. You have to decide how you're going to use it (slow fire, long strings, hunting, etc.) and then decide if you're willing to pay for setbacks and new barrels and then once you've told yourself how much you're willing to spend, then choose your cartridge.

That being said, you want mag fed and a SA, so if you are okay with potentially having to rebarrel in less than 1500 rounds, then 6.5x284, 6.5 SAUM would be my choice. I think the 7 SAUM might be too long if you want to run the 180gr bullets, but you might get away with 168gr bullets in a 7 SAUM and a SA though. The calibers with the most potential for barrel life longevity are probably the 260rem, 6.5x47L, and the 6.5 Creedmoor, all of which can get to 2800-2850fps (26" barrel length region) with a 140gr pill and decent barrel life, maybe in the 1.5-2.5K range.

Now, if you want to fireform or are okay with fireforming, the 260AI is a good choice. The 6mm are good choices also. 6mm creedmoor is very propular on the PRS circuit as is the 6x47L and they are relatively easy to size from its parent cartridge. 243 and the 243AI are good as well, but barrel life is also not very good there.