Range Report: 7mm RB No.5 100 yard update

[FatJackDurham]

I went to the range again today, this time with four .284 rounds, and four .287 to compare at 100 yards. First, let me say, I am certain my marksmanship is the primary factor. The sights are darn hard to see. I am thinking of taking them off, filling the round edges out and rust bluing them in a rough matte finish. On the rear sight, there was a little nick right near the notch that was shining like the Christmas star....

Anyway, I shot 41 grains of I4350 in the 175 grain .284 round nose soft point bullet that came with the Winchester box. It definitely didn't shoot as well as the .287. For the Buffalo Arms 154 grain .287 soft point spitzer round, I used 42 grains, which I hadn't tested. Both loads were the minimum for the Lyman book.

The slower, heavier .284 bullet shot about 8 inches low, so I raised the sight to "200" for the other three shots. Then dropped it back down for the .287. I didn't set up my crony, but any ciphering I do on my ballistics program shows that the .284 could have been as slow as 1900 - 2100 fps, while the .287 was around 2500. Does that sound right? There must have been a lot of blow by from the poorly fitting bullet to allow it to drop 8" at 100 yards. Still, all four were on the paper.

As soon as I get a change, I am returning the 160 grain lead bullets for a sample set of shorter projectiles to see if they will fit the throat, and if so, I'll compare lead to jacketed.

Here is the first target, .284 175 grain bullet with 41 grains of I4350. About a 5 x 2.5 inch group.


Here is the .287. Its about 4 x 1.5 ". The fact that its pretty flat, and I have about a 12 lb trigger pull gives me some hope. If I can improve the visibility of the military sights and work the trigger down to about 7 lbs, maybe I can get the group down to 2 " or less. This is all open sights off of a sand bag. If someone has a lead sled at the range some time, maybe I can try it from a rest.

[Mike Armstrong]

Jack, is this an original Remington sporter (a rare bird!) or an ex-military rifle?

And you don't say what the bore condition is. That certainly affects accuracy, as in any rifle. My three had the condition all over the place; the oldest a '97 "RM" (Republica Mexicana) marked rifle had a nearly pristine bore with a tiny amount of frosting in the leade. The unmarked '01 rifle had a truly horrible bore which was rotted badly in on lands and grooves. Finally shot about a 6" group at 100 yds but fouled really badly and made random "patterns" after the first group. The '01 carbine marked "R. del E." (old name for Uruguay) was pretty decent but the recoil with full loads was so extreme I couldn't really make it group; even at 50 yards I would get about 1 foot groups....finally sold it to a Remington collector.

Neat guns with a lot of history; thanks for posting about yours! Let us know how things progress.

[FatJackDurham]

Mine is a military M1910, made between 1912 and 1916. Bore is fair, I'd say. Stong rifling but dark in the grooves. I have cleaned it down to the metal as far as I can tell. It picks up copper fouling from the jacketed rounds, but I shot my best group yesterday with rounds 40 - 46. Today, it shot best at rounds 10-16.

With the tightest patch and jag, it feels rough, but so does my Springfield M1884, and it shoots pretty well.

I think I can get this to shoot two inches. I am at four now, with an untested load, and bad sights. I plan to square up and darken the sights a little and see what I can do to make a better sight picture. Plus, once I get the full length sizer die and I can tune my load and brass consistently, I think it will tighten up.

Hey, how about some pictures of yours?

[Ben_Rumson]

I think the .284 bullets will leave far less metal fouling in your bore than the .287s...
For testing @ a hunnert you need to mount a scope... IRRC the screw size that fastens the rear sight onto the barrel of your roller are 8-32 or 10-32... after you determine what size they are take a Weaver base for a 336 Marlin, drill out & counter bore one of the holes to take a socket head screw so it sits flush... After that drill a new hole at the appropriate spacing point and treat it the same as the first hole you did... Two screws is adequate to hold a scope down for testing... It worked for me on a 50-70 roller shooting 450gr lead bullets...The screw length is critical though... Too short, you run the risk of the screw pulling out of the threads in the barrel when you cinch them down... Too long and they'll bottom out before they're tight... When things are right.. service removable thread locker is good... You'll be surprised at how accurate that old rifle will shoot when you don't have to overcome the crappy military sights...First 7mm roller I had I ground a Lyman receiver sight to match the contour of the roller and epoxied it in place... That thing was crazey fun & accurate, It held until I had an A/D with a 95 Mauser 7mm(Timney Trigger set too light) that smacked my roller square on the receiver from 2ft away which spun that rifle around a few revolutions and left a piece of the jacket sticking out of my thigh...Good Groups!

[Griff]

Let me first say, that it's an extremely rare day when I could any FIVE diifferent loads with SAME bullet and have one of them prove to be the best load for that rifle. I've sometimes went thru 4 or 5 powders with several bulletts before I found that right combination of components. Sometimes that grouup of 5 would point me in the right direction... but just as often it was not.

Take heart, it's no simple task to start from scratch and find an accurate load.

[GoatGuy]

I'm not much of a 7mm guy ...never really fooled with them ...so not any help coming from me. Like Griff said though, it should eventually come along if you keep working on it.

[FatJackDurham]

IRRC the screw size that fastens the rear sight onto the barrel of your roller are 8-32 or 10-32... after you determine what size they are take a Weaver base for a 336 Marlin, drill out & counter bore one of the holes to take a socket head screw so it sits flush... \

OH!!!! Fantastic!!!!! What a great idea! Have the Weaver base for my Marlin 1895 Cowboy, too! But... I have no scope... I sold them all... I'll have to bum one off my neighbor...

Man, now I cant wait!!!!

[FatJackDurham]

Take heart, it's no simple task to start from scratch and find an accurate load.

Yep. I'll work it in. My big limitation is that I don't cast my own yet. In fact, Montana Bullet Works is the only place online I found that casts 7mm, so my options are limited. Also, I am trying to avoid spending too much on this gun, its the only one I could actually sell for more than I have in it so far....

[Griff]

In the meantime, do some research and find out what the military that used the rifle used. If they used a 180gr @ 2500fps, start there. You nat hafta go up or down in weight or velocity, or sone permutation thereof, but you'll be in the ballpark.

[Mike Armstrong]

Jack, thanks for the info on your RRB. 1910s aren't real common, for sure. I've seen a couple, one in 7x57, the other in 8mm Lebel. They are rumored to have been made in 7.62x54 Russian, and .303, too, but those not common to say the least.

My RRBs all went to collectors or other shooters back in the "little slump" we had in the early 1980s--house payments had to be made....and I'm not much of a picture taker, anyway. There is a decent Uruguayan saddle ring 1901 (I think) carbine in a local gunstore, at the usual Richifornia premium price, for sure.

I always wonder about these lightweight carbines chambered for powerful ctgs. (I still have a Mexican FN Model 1924 Police Carbine with a 16 1/2" barrel in 7x57....). I find recoil sort of goes away when you are shooting at game because of the pain relieving qualities of adrenaline. Suppose that it is even MORE effective when the "game" is shooting back? I guess these guns weren't made for paper punchin', anyway.

I fired my RRB carbine with Venezuelan-issue 1935-dated FN military spitzer ball back when I had it. The ammo was made for machine guns or the FN Type "D" version of the BAR. Spectacular blast, fireball, and RECOIL! Carbine took it better than me.....

[Nath]

Is there any compression on the pwder?
I always found 4350 likes some compression!

N.

[FatJackDurham]

The higher end load uses some compression, though I dont want to try that until I sort out the case resizing.

There aren't any markings on this rifle that would help me identify the army it belonged to.

[Mike Armstrong]

As I understand it, most of the smokeless powder RRBs, rifles and carbines, were not identified as to contract by marking the rifle. Mexican rifles ordered by the Diaz dictatorship were mostly marked "RM" or "E de M" (Ejecercito de Mexico=Mexican Army) and most of the Urugauyan guns (all I've seen were cavalry carbines) were marked with the present name of the country or its former name.

But a lot of these guns went to factions in civil wars and governments we didn't consider legitimate and were unmarked, or at least unmarked by Remington. "Black" rifles before there were "black rifles," as it were. As the British used to say, "No names, no pack drill." I would bet the rifles on the infamous "Ypiranga" were unmarked as to end-user, even though the shipment was made in Ilion, NY! After all, we weren't actually at war with Germany. Yet.

I can't remember if the 8mm Lebel RRB I once handled was French-marked or not, but I suspect it was.