Gunsmithing l/a 7rsaum freebore

[wvlapua]

I have searched but have not gotten a good answer for the l/a. I will shoot berger 180 hybrids and possibly 195's when/if available. Since I'll be running a long action with 338 mags seating depth is not a problem. Someone had a .188 and wished they had .220. But then I read the new 180 hybrids are actually different than the originals and don't require as long a freebore. I want to maximize case capacity and still be able to chase the lands a bit with the 180's.

What freebore 180 hybrid combo works for you guys running l/a 7rsaum? And what is you coal length and length to ogive?

 

[jonaddis84]

The 188 should do what you want, the 220 I dont think youd be able to chase the lands, as it is you probably wouldnt have much bearing surface in the neck with that fb.

I run the 188 with 175smks and 0.015" off the lands and I barely have a caliber of bearing surface in the neck. The Bergers tend to have their ogive not too far off the SMK's in reference to the boattail due to their vld profile compared to the smk, so Id say youll be close.

I have some 180 hybrids on the way finally so I can try them out, but wont see them for a few weeks probably from powder valley

 

[wvlapua]

Thanks Jon..I actually just got my shipment of 180 hybrids. I'll have to do some measuring. I saw somewhere ths 195's are projected to need .238 in the saum. But I'm definitely more interested in running the 180 for now.

 

[milo 2.0]

WV,
I have my reamer sheet right here, says .188 throat, .204 lead, this is my newest saum, the older one has a way longer throat.
The first numbers are easier to work with. I don't have 180's loaded for either gun at the moment, I start out with 175 xld's till the throat is gone, then switch to the 180, and will be soon on the older gun.
Here's the numbers for the .188, with Hornady comparator, I think I'm .005 in.
"3.230"
"3.040" COAL
This reamer laves ample room to chase the lands, with some bullet still in the case.

Other one, don't know what FB is???
"3.309" with comparator,.005 in
"3.112" COAL

The depth with the comparator should be close to what the 180 would run, minus say .035.
I hope this helped, I'n no reamer reader! I really like the .188 better though.

Bullet length with comp.
175- "1.741"
180- "1.775"

 

[jonaddis84]

Thanks Jon..I actually just got my shipment of 180 hybrids. I'll have to do some measuring. I saw somewhere ths 195's are projected to need .238 in the saum. But I'm definitely more interested in running the 180 for now.

If no one else chimes in, and you want to send me one bullet I'd be glad to measure for you with a virgin chamber. Pm me if so.

Galaxy S3 on tapatalk

 

[wvlapua]

Thanks milo..Jon sending pm.

 

[milo 2.0]

Thanks milo..Jon sending pm.

You want the hard numbers for the 180, I'll take my bolt apart and get them, I have the bullets and new brass. The new gun with .188 throat has less than 100rds through it, so throat should be intact.
These numbers really don't mean jack shit to me, if I was experiencing pressure with the lesser one, I'd look into it, but it's not, it's running at 3040fps, and I can get it to 3075 and the 180 should be no different.

 

[wvlapua]

I'd be happy with velocity in those numbers..I'll be running a 30" tube. Hope to get 1500 rounds out of the barrel. I may melonite, still undecided. I was under the impression the 175xld are longer to ogive than the 180 hybrid.

 

[milo 2.0]

I'd be happy with velocity in those numbers..I'll be running a 30" tube. Hope to get 1500 rounds out of the barrel. I may melonite, still undecided. I was under the impression the 175xld are longer to ogive than the 180 hybrid.

If you're going from base of the bullet, to the end of the bearing surface, 180 is longer like the last numbers I posted before.
The bearing surface on a 175 measures, .540
The bearing surface on a 180 measures, .574
The bullets are identical in length, w/o comp at .1.542, minus the shitty tips. In late 2011 they added about .020" more bearing surface to the 175.

Oh, my tubes are 24& 24!/2, my 30" Mcgowen barrel ran at 3160. Anyone could live with that!!!

I got 2900 rds out of the McGowen, after 900, switched to 180's, 1900 set the barrel back 2 1/2", shot 1000 more before shit canning it, but it was still shooting.

 

[wvlapua]

Thanks for the real world numbers. That's some pretty darn good barrel life to. What is your powder of choice for the long tube? I have a jug of H-1000 on the way.

 

[milo 2.0]

I started with Norma MRP 2, run VV N570 only today, 67.5, and 68.5grs.
H1000 just pressured up for me with no speed, Retumbo pressured up at 64gr with a 162 amax, couldn't justify trying it on a heavier bullet.

The older barrel is nitrided, at 650 I bore scoped it, the throat looked new, I'm hoping to get 1350 out of it before switching bullets. This is a 24" Brux, and speeds are around 2850fps, never been happy with that, but this thing shoots, first time out shot a 2 1/2" group at 1320, and just about anytime I go out, I'll shoot a rapid fire group from 700-1000 yards and it'll stay 2-2 1/2".

 

[wvlapua]

Meloniting didn't hurt that barrel at all..good shooting. Doubt I'll get as much velocity since I usually shoot at 1025' asl. I'll be searching for some
VV N570. Still hoping H-1000 does the trick as others with long tubes seem to have good results with it. When I first started researching powders it seemed tubes under 28" 4831sc was the ticket and 28" and longer H-1000. I did notice someone else using the VV N570 and Magpro with great results. Can't wait to get this thing finished and at the range.

 

[milo 2.0]

I sure hope you have brass, it's virtually nonexistent. Norma also released 217, betwen MRP and MRP 2, slower than N560, should be in country shortly. Norma powders rock when they work, a little pricier than regs, but considerable less than the N500 series.

 

[wvlapua]

I have just enough rem brass for the time being. Hopefully picking up 40 more pieces tomorrow. I was hopeful midway would have it this month as previously projected, but that didn't happen. Missed a few opportunities here on the hide to..Damn overtime. I have no experience with any powders other than the regs. Thanks for your help sir.

 

[milo 2.0]

Remington is supposed to run some the first week in May, but given today's market, I can't see it happening. They've postponed the last five runs. Remember my name, I have a bunch, but leary about letting it go.
You can get the ammo plant number on Rem's website, they'll keep you informed.

 

[wvlapua]

I have emailed them a few times with no response. Thanks for the hint. When it does become available I'm gonna have to act quick..lol. I'll definetly keep you in mind.

Now I just need to decide whether or not to melonite and what brake to run. I'm between little bastard and ross schuler.

 

[lvgolfer962]

Now I just need to decide whether or not to melonite and what brake to run. I'm between little bastard and ross schuler.

I started with the .188 reamer.

Its a 30" krieger #17 1-8.5
Im at 1550 to 1600 rounds down the pipe and shes still going strong.

My Load has been
H1000 62.3 in nosler or 63.3 rem brass(all necked down 300 saum)
180 bergers(doesn't seem to matter which ones, they all shoot the same)
Chasing the lands so length varies
tula lrm primers

avg speed is 3050

It can go faster but the 3000 mark just flat out shoots

Tried retumbo, but couldn't get enough in the case to make it work with the 180's
Im running a ross brake on mine, love it!

This cartridge continues to impress
Well worth all the hassles of finding brass and short barrel life!!!!

 

[wvlapua]

I started with the .188 reamer.

Its a 30" krieger #17 1-8.5
Im at 1550 to 1600 rounds down the pipe and shes still going strong.

My Load has been
H1000 62.3 in nosler or 63.3 rem brass(all necked down 300 saum)
180 bergers(doesn't seem to matter which ones, they all shoot the same)
Chasing the lands so length varies
tula lrm primers

avg speed is 3050

It can go faster but the 3000 mark just flat out shoots

Tried retumbo, but couldn't get enough in the case to make it work with the 180's
Im running a ross brake on mine, love it!

This cartridge continues to impress
Well worth all the hassles of finding brass and short barrel life!!!!

That's the exact barrel contour brand, aprox finish length and twist I have. I was originally not going to run a break since it will be such a heavy rifle. It will be in a mcm a5 that weighs over 4lbs with bm and empty mag. Will be screwed to a stiller tac300. Wish I could have gotten some of the brass you had listed, but I have enough for a while.

 

[lvgolfer962]

That's the exact barrel contour brand, aprox finish length and twist I have. I was originally not going to run a break since it will be such a heavy rifle. It will be in a mcm a5 that weighs over 4lbs with bm and empty mag. Will be screwed to a stiller tac300. Wish I could have gotten some of the brass you had listed, but I have enough for a while.

Ive taken like 4 shots without the brake, and that was enough for me lol! The ross brake makes it feel like a mild 308, no problems staying on the scope and seeing impacts.

Mines in a mcree chassis, with the scope and bipod its over 19 pounds.

That brass went quick!
I managed to accumulate over 1000 pieces in the past 6 months, and just had to get rid of some.
Its out there, you just have to be in the right place at the right time

 

[Tac284]

I am fixing to build a 7 saum myself. Are you guys using 4 groove or 5r krieger barrel's? I am still trying to find brass, I do have one piece which is nice to look at but I don't think it's going to get me by.

 

[lvgolfer962]

I am fixing to build a 7 saum myself. Are you guys using 4 groove or 5r krieger barrel's? I am still trying to find brass, I do have one piece which is nice to look at but I don't think it's going to get me by.

Mines a 4 groove krieger.
I wanted a 5r but wasn't going to wait 6 months to get one. This one has shot so well that i just went ahead and got the exact same barrel to replace this one when the time comes

 

[Tac284]

I am in the same boat, I want to try a Krieger 5r but I am not going to wait. I can buy a HV krieger 4 groove right now and be done with it. I'm sending you a pm lvgolfer962.

 

[jonaddis84]

Keep an eye on Powder Valley, theyve been getting the Nosler 300 brass in every once in awhile. I have another 200 pieces of it coming, not sure if Im going to keep it all or not yet, Ill make a post in here if I decide to get rid of any before putting it in the FS section.

 

[wvlapua]

Mines a 4 groove as well. Got it from Bruno..no wait. I scored another 140 pieces of remmy brass today. 80-300saum and 60- 7rsaum. Drove 76 miles one way to get it and paid nearly a buck a piece.

 

[DDoug]

I have a Saum in the works right now also. I'm waiting on action right now but I have two Bartlein 1 8/5 5r barrels at 30 inch ready to go. I ordered my reamer from PTG it has a 188 free bore. I went with a 317 neck hope I don't have to neck turn to much. I have also been looking for some good loads.Looks like I may need to look at VV N570 I have a small keg of H-1000 handy as this is what I have read worked well in the longer barrels. But this brass thing is looking sad I have 50 pieces of 300 saum Rem and I also missed out on the brass sale on here. You snooze you loose HaHa! I hope Rem makes some Brass sometime this year. You guys that have brass which do you prefer Rem or the Nossler I have passed on some Nossler a few times may have to go that rout.

 

[jonaddis84]

Get the nosler, I think it's better quality than lapua out of the box. It comes with chamfered flash holes and nicely chamfered necks as well.

Also 317 is a no turn neck, although it is very tight, I think my brass only grows 0.002 or so maybe less, it's so little that it will still hold a bullet in the neck, you can slide it in and out by hand though.

Galaxy tab 10.1 on tapatalk

 

[wvlapua]

If no one else chimes in, and you want to send me one bullet I'd be glad to measure for you with a virgin chamber. Pm me if so.

Galaxy S3 on tapatalk

Jon, have you had a chance to get some measurements?

 

[jonaddis84]

Sure did, as you can see you won't gain much with a longer free bore with this bullet as you won't have much bearing surface left in the neck.

That's 3.107 overall length. I don't want to give you ogive length as I make my own comparator bushings so they're not necessarily standard hornady diameter.

Sorry about that last picture if anyone happened to see it and wonder wtf, apparently had two pictures named the same on the site.

Galaxy S3 on tapatalk

 

[jonaddis84]

Never mind, that didn't take long, it's all gone sorry.

 

[Tac284]

Ordered my reamer couple weeks ago and it's almost the same as yours but the neck is .318, In your picture what bullet is that?

 

[jonaddis84]

180 hybrid

Galaxy S3 on tapatalk

 

[Tac284]

What was your original cartridge overall length? I'm just wondering if I need to get a shorter freebore? Maybe .175