Building 257 Roberts on Browning Safari Sako. Wondering if I can seat bullets out farther that 2.800 inches. I will modify mag box if it will work. Thinking copper bullets. Hammers etc
257 Roberts Seating depth
- Thread starter MooseHunter
- Start date
Seat a bullet so the boattail is about even with the neck/shoulder junction then see how it fits magazine and how much you will have to alter mag. Keep in mind monolith bullets can be much longer so rifle barrel twist must be able to stabilize that longer length.
I am working with Sako basically a 579. The 90 gr Hammer was on my list. Barrel I am using is 9 twist. According to hammer 10T will work. Wondering how much I should mess with mag box. The gunsmith will figure this out as he will have the reamer and the box in hand. I may send him some dummies seated long and he can adjust COAl/box to reamer.
Does anyone run 62,000 PSI in .257 Roberts these days? Dont see how it would be a problem in modern action but figgered I would ask.
Does anyone run 62,000 PSI in .257 Roberts these days? Dont see how it would be a problem in modern action but figgered I would ask.
If both cartridge's are run at 62,000 what is the velocity gain of the AI?
Good question. I've no pressure test equipment. Haven't worked with a standard Roberts for a few years, but about 7-10% seems about right. With my latest 257 Ackley; long action 700, 9 twist, OAL pushing 3", I'm knocking on factory listed 25-06 speeds with 100s & 115s from a 24" barrel. Brass life is good, primer edges are round, & bolt lift is normal. Re: copper... So far it seems to like the Barnes 80s & 100 TTSX pushed hard, but more testing is needed.
Case life is quite often better with improved cases, but am thinking it depends on brass, chamber, & die dimensions jiving happily. My 06 Ackley doesn't seem to agree with Lapua 06 brass as it's a bit larger at the .200 line than 90s era WW brass. Between my chamber & the Forster FL die, the WW brass goes many firings w/o trimming, the Lapua needs trim every other firing. Correlation isn't necessarily causation but is how I'm seeing this situation until proven otherwise.
I have a Ruger ultra-light from the 80's in .257 Roberts. I tested a lot of different lead-free bullets in it from 80 to 100 grains, different depth settings, etc. One of Barnes' recommended powders (Hunter) worked best (I use 43.2 grains) along with the 100 grain TSX. This was with Remington cases and CCI BR2 primers. Get just under 1/2" MOA, not bad for a pencil barrel. Those Barnes (and most all lead-free bullets) really show improvement in all of my rifles (I use them in about 8 different calibers) when the bullet is allowed to jump. So, I think you might be disappointed when you try them close to or into the lands. If they shoot terribly, just try backing them out. Mine were loaded at 2.780" OAL, as ironically recommended by Barnes. They test at these depths and sometimes that translates well in other rifles. It did for me. They shot like crap further out. I'm not bothered by single-feeding when hunting, but the load has to work well enough to warrant doing it.
If I were going only after average-sized white tails or smaller, I'd probably look at the newer 85 grain bullet which wasn't available when I did my testing. In my 7 MM Rem Mag, I started out with pretty heavy, working down to 150, 140, then settled on the 120 for the hunting I now do. The 120 knocks pigs down with great authority, so I feel pretty good about the penetration - and they do open up quick.
If I were going only after average-sized white tails or smaller, I'd probably look at the newer 85 grain bullet which wasn't available when I did my testing. In my 7 MM Rem Mag, I started out with pretty heavy, working down to 150, 140, then settled on the 120 for the hunting I now do. The 120 knocks pigs down with great authority, so I feel pretty good about the penetration - and they do open up quick.
Last edited:
Simply running a cartridge with less powder volume at the same pressure is not the answer. The Ackley with more powder volume produces more velocity with that additional powder volume while at similar pressure. You still need to add more powder to produce more velocity.
True. I just wonder what pressure people run the Roberts at these days. The + P is specd at 58 000. Seems mild in modern rifle
What I am trying to figure out is the Ackley vs Creedmoor
It seems the Standard .257 has more case capacity than the Creedmoor and the Ackley more yet. On hogdon website the standard or +P roberts seems to run on the heels of the creedmoor with less pressure.The AI version takes the lead at similar pressure. Ofcourse more volume as well. The Creedmoor seems more practical especially for long range High BC bullets. But I am building a custom rifle so where is practicality come in? I have a 25 06 7 twist for that. I have the Browning Sako action and a new 9twist barrel. I will use this rifle for groundhogs to deer or antelope. It seems the +P version would do all I want to do as well as the creedmoor would. The AcKley would be beneficial in that the extra case capacity could be used with longer bullets(Hammers) without modifying the mag box and get into throat issues. So the practical way around that is pick a Hammer that works in the 2.80 mag box and seats in case a bit or just pick a Hammer that works in 2.8. So I guess the real question gets down to the +P or the Ackley. Either one is cooler than the Creedmoor. Anybody can have a creedmoor even though it seems practical. I appreciate your response to my post! Please give me your honest opinion and the benefit of your experience on my dilemma. I am building a light rifle to carry and hunt with.
Don
It seems the Standard .257 has more case capacity than the Creedmoor and the Ackley more yet. On hogdon website the standard or +P roberts seems to run on the heels of the creedmoor with less pressure.The AI version takes the lead at similar pressure. Ofcourse more volume as well. The Creedmoor seems more practical especially for long range High BC bullets. But I am building a custom rifle so where is practicality come in? I have a 25 06 7 twist for that. I have the Browning Sako action and a new 9twist barrel. I will use this rifle for groundhogs to deer or antelope. It seems the +P version would do all I want to do as well as the creedmoor would. The AcKley would be beneficial in that the extra case capacity could be used with longer bullets(Hammers) without modifying the mag box and get into throat issues. So the practical way around that is pick a Hammer that works in the 2.80 mag box and seats in case a bit or just pick a Hammer that works in 2.8. So I guess the real question gets down to the +P or the Ackley. Either one is cooler than the Creedmoor. Anybody can have a creedmoor even though it seems practical. I appreciate your response to my post! Please give me your honest opinion and the benefit of your experience on my dilemma. I am building a light rifle to carry and hunt with.
Don
A few years back I bought a Bartlein 2B 10 twist barrel for my 257 Roberts built on a long action Browning A Bolt. I had the throat cut for a 120 gr Speer SPBT specifically. I load H 100 V and get 2925 fps from it. That's 50 fps slower than my 25-06 with the same bullet. No pressure signs and I could probably squeeze some more velocity out of it before it started showing pressure. It just shoots to good where its at. I haven't picked up my Browning A Bolt 25-06 since I got the Roberts back. Good luck. The Roberts definitely benefits from a longer action. If you're confined to short action you're gonna be hampered in my opinion.
The Roberts will whoop the creedmore if carefully handloaded. Moreso for the Ackley Roberts. No replacement for displacement. Heresy, I know...
If you're buying a reamer, the newest developments in throat geometry can be incorporated to modernize the old girl. A 3" magazine will also do good things with longer bullets, if rifle is throated for same. Recoil will still be negligible in a light rifle.
Shame to have a 9 twist & not use the 110-115s.
Here are some bullet lengths for reference. BTO is with my Davidson comparator, & will likely be different than yours:
80gr TTSX is 1.015" BTO .440
100 Sierra FB Spitzer is .955" BTO .476
100 TTSX is 1.193" BTO .620
115 Ball.Tip is 1.218" BTO .630
115 Berger is 1.187" BTO .540
Edit for clarity.
If you're buying a reamer, the newest developments in throat geometry can be incorporated to modernize the old girl. A 3" magazine will also do good things with longer bullets, if rifle is throated for same. Recoil will still be negligible in a light rifle.
Shame to have a 9 twist & not use the 110-115s.
Here are some bullet lengths for reference. BTO is with my Davidson comparator, & will likely be different than yours:
80gr TTSX is 1.015" BTO .440
100 Sierra FB Spitzer is .955" BTO .476
100 TTSX is 1.193" BTO .620
115 Ball.Tip is 1.218" BTO .630
115 Berger is 1.187" BTO .540
Edit for clarity.
shoot4fun
Gold $$ Contributor
The Tikka rifles come to mind when you talk about the limits of bullet seating, as they are usually (factory mags) well short of the free bore.
For the 257 Roberts it seems the COAL has the bullet seated very deep in the case. I owned a Kimber 84M Hunter and it too suffered the deep seat issue due to mag length limitations. It went away for a beautiful Ruger No.1 in the 257 and now I can get them seated out longer. Most 257 Roberts rifles are built on short actions I think and that, IMO, and that will limit them as well.
Good information. I plan on the 110/115s for sure. I get 2950 with the Speer 120 boat tail in 9 twist 25 06 24 in. That has been my bullet of choice for many years. Excellent results. Yes the short action will hamper things a bit. Might squeak a little length but not much. So the real question becomes to Ackley or not? I would like the info on that reamer for improved throating. "No replacement for displacement" Amen
Out of the bullets listed above only the 80TTSX & Sierra 100 FB Spt. will keep the base of the bullet above the neck/shoulder junction at 2.800". Checked the Speer 100 Spt & it will be OK. The Sierra 117 SptBT barely intrudes on powder space as does the Speer 100 Varmint HP. The Hornady 110 is deep into the case. Same should be true with the standard Roberts. Still more capacity with the Ackley, but not quite as much with the heavies at 2.800".
Reamer maker should be able to fix you up with the newer throat geometry if you go that route.
Hopefully you have a source for Roberts brass because not much is available for the x57 clan these days. Norma did a run of 257 a few months back, but it disappeared like the proverbial drunken sailor's pay first night in Hong Kong. PPU has 6.5x57 which has worked pretty well, & then there's the odd stuff that pops up in classifieds now & then. Making sure you're aware of this before diving in & then not being able to find brass.
Reamer maker should be able to fix you up with the newer throat geometry if you go that route.
Hopefully you have a source for Roberts brass because not much is available for the x57 clan these days. Norma did a run of 257 a few months back, but it disappeared like the proverbial drunken sailor's pay first night in Hong Kong. PPU has 6.5x57 which has worked pretty well, & then there's the odd stuff that pops up in classifieds now & then. Making sure you're aware of this before diving in & then not being able to find brass.
Good point on brass. Is the PPU good stuff? I found some 7mm PPU. Maybe I should stock up.
It aint Lapua, but it's not too bad. The 6.5 necks down easy to 257. My chamber didn't need to neck turn, dont remember necks thickening much. Good for setting positive headspace on 1st firing too. Screw the FL die down slowly until it fits snug in your gun on 1st firing & there's no question of sloppy fit. Fireformed 25 so far out of the last batch. Haven't lost any after at least 7 or 8 firings. It's pretty stout stuff; didn't blow out the body nearly as easy as older WW brass.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.