I think that this S&B load has a RN bullet. I use RWS H-Mantel, which is also roundnosed.

So a RN bullet, 175 grs? seated very long should be a starting point. Do You have at least one factory round to compare?

What dies do You use? Make? 7x57 with other shell holder?

good shooting! H

I do not have a factory round to compare. I am however seating the projectile well out.

Both barrels are being fed identical loads.

Bottom barrel seems to shoot far to the right. Well off the target board.

quote:

---

Originally posted by siviter:
I have just purchased a CZ BRNO 300 series double rifle. Top barrel is very accurate. Prob is regulating the bottom barrel.
Can anybody suggest hand loads for this rifle that will work with the factory regulation? it was I understand regulated for 173 gr Sellier Belliot loads. I have tried emulating this load with a 175gr hornady RN pushed by 44gr Winchester 760 for about 2500 fps without success.

---

Siviter, I think your velocity calcalations are a little optomistic to say the least. My experience is that 44.0 grs of Win760 with a 175 gr Hornady will yeald no more than 2250 fps , and the factory round for 7x57 Mauser is only 2296 fps with a 173 RN, and the "R" version will be about 5% less.

Selier & Bellot 7x57R with 173 gr sp, is usually avaiable from: www.cheaperthandirt.com for only $8.79 per box of 20. They happen to be out right now, but they had it in the store last week. Give them a call and they may have some coming in.

I load for many double rifles, and one thing you will find, if you don't already know, will be that the rules you load for a single barrel rifle do not apply to double rifles. Double rifles are a zebra of a different stripe, so to speak! If this is your first double rifle, then the first thing you need to do is, buy a copy of "SHOOTING THE BRITISH DOUBLE RIFLE" by Graeme Wright. It is available from: Huntington Die Specialities. This book will explain many things to you.

I think I understood you to say your rifle is an O/U. If this is the case, the loading will be easier, note I said "EASIER" not easy! The first thing you need to know is you do NOT exceed speeds in a double rifle.
What is each barrel doing as far as group? What I'm asking is is the bottom barrel hitting high, and the top barrel hitting low,or vice versa? If the barrels are crossing before they get to the target distance, the rifle was regulated for, what you need is more speed, and recoil to bring them together. If they are shooting appart( this is top barrel shooting high, and low barrel shooting low), then you need to back off. Most 7x57R rifles were regulated to 100 yds. And yours is probably no exception.

The way you hold the rifle to shoot is critical, in other words, the rifle absolutely must be allowed to recoil in the manner it would when shot off hand, because the recoil, and rise of the rifle is where the regulation comes from. It is OK to rest your fore hand on a bag, but not the rifle. Nothing should touch the rifle other than your hands,shoulder, and cheek!

You may E-mail me dirrectly and I will help you in any way I can, but don't get discouraged, once you find the load for this rifle you will be hooked on double rifles. I'm 64 yrs old, and I bought my first double rifle at the age 22, and I have owned many since then, and though they take a little learning to load for they are worth it!

------------------
..Mac >>>===(x)===>

[This message has been edited by MacD37 (edited 06-14-2001).]

quote:

---

Originally posted by siviter:
Loads for both barrels are the same. The rifle is being shot in over a vehicle hood with support of a rolled up parka under forend.

Both barrels are being fed identical loads.

Bottom barrel seems to shoot far to the right. Well off the target board.

---

You should test a combination gun as follows: hold the gun as You would in hunting. You should place Your arms on bags to reduce tremble, but Your left hand has to be at the forearm not anywhere else.

Check the firing sequence: an O/U is fired: one shot lower bbl, ~ 5 seconds later upper bbl. Let cool completely, then repeat same sequence. Look up group size.

On S/S: first right bbl, then left. Let cool. Repeat.

Now, I know of one Brno/CZ model where in rifle/shotgun the rifle bbl is on top. This model You may recognise by the side plates of the receiver being broader than the bbl assembly, enclosing the bbls, forming a step on the side of the gun. ( 500 series and Super series are different ).

On this guns firing sequence might be reverse. Just try it: two shots and You will know: fire upper bbl ( forward trigger ?) then after 5 sec lower barrel. Check if the sequence of the triggers or trigger may be changed. Perhaps an extra knob or push the safety sideways. Perhaps You have to remove the bbl assembly to change this.

If You need info on the ballistics of that particular round or the looks of it,just post this, I will look it up. H