175 Grain Bullet in Normal No Alterations 275 Rigby HS

[Bob Nelson 35Whelen]

Every rifle barrel off the lathe is different. (dull reamers sharpened undersize, fresh reamers, over/under throated that day, etc.)

What you need is a Hornady OAL gauge: https://www.hornady.com/modified-cases#!/

And you need a Hornady 7x57 brass OAL cartridge for it: https://www.midsouthshooterssupply.com/item/00005a7x57/lock-n-load-a-7x57-mauser-modified-case

That will let you place your desired bullet into the gauge, push it into the chamber, thrust the bullet forward in the case until it hits the lands, and then withdraw the fake cartridge. You'd then measure it to figure out the true OAL of the potential ammunition if it were loaded to touch the lands. You want at least .020" off the lands to prevent a pressure spike, or more if it gets more accurate shorter, or more if it is still longer than the maximum COAL of 3.045", or shorter if it won't feed from your internal magazine.

With the measured facts, you'll know if you can use a 175gr bullet of a given type, and if so just how deep in the case it would require. (which would inform you if you're accidentally creating compressed loads)

@rookhawk
I'm not that rich to own all that fancy gear.
I do it one of 2 ways.
1) using two people I drop a cleaning rod down the barrel to the bolt face and make the cleaning rod at the muzzle.
Then remove bolt and place desired projectile in the chamber.
Person 2 GENTLY holds said bullet in place with a length of small dowel.
Reinsert cleaning rod in barrel and Mark again.
This gives coal to the lands.

2) Partially neck size a case and partially seat a projectile. Blacken projectile with sharpie or candle smoke.
Chamber round, projectiles will be pushed back in the case and any land marks will show up.
This will give you max coal.

Once max coal is established desired seating depth can be worked out.

If all else fails just use book recommendations.
Has worked for me for a lot of years.
Bob

 

[Bob Nelson 35Whelen]

@franzfmdavis
To me personally that pretty piss poor manufacture service.
When ever I have had a rifle built my gunsmith ALWAYS asked me what the biggest bullet I planned on using and set the throat/ leade to suit that. Shorter bullets DONT SUFFER, they may need a longer jump but by being able to seat lighter bullets out further you can put more coal on the fire for higher velocity and do it safely.
Weatherby have been doing this for years.
To me personally a manufacturer should produce a rifle to handle the longest available projectiles to suit the calibre. Dang even the little 308 will chamber a 220gn factory loads.
For the price of a Rigby you would think they would get it right and not expect the customer to pay to have it modified to suit. Should be done at the point of manufacturing in my book.
You don't see a SAKO or tikka or other European brand that won't chamber a factory 175 gn load in the 7x57.
I don't suppose you would have to send a 30-06 back to have the throat fixed for a 220-240 round nose
Bob

That’s good to know for future reference!

When I was looking into it, I spoke with a tech at Rigby and with JJ Peredeau, both of whom recommended that I lengthen the throat. Rigby also mentioned that they offer throat lengthening as a customization on new rifles. None of them offered the other option you described above.

I did ask whether there would be any negative impact on using smaller bullets, such as the 140, after the throat was lengthened and they said no.

In retrospect, I am still happy that I lengthen it because I subsequently had the flexibility to develop a load using the 175 grain Northfork bullet that will hit the same point of impact at 100y as the 140g Hornady bullet at 100y, allowing me to use my scope and irons for either bullet.

I can imagine that if I was restricted in fps due to reduced case capacity, that may have become more difficult or not possible?

 

[Rare Breed]

Just as an example for comparison, I have a 2017 Highlander Stalker and was not able to load 175g Northfork Semi Spitzer round. I sent it to JJ Peredeau who opened up the throat in the rifle. The cost to do it exclusive of shipping was less than $300.

Frantz, what is the COAL you are using with your 175 grain bullets for your 275 please? I see different information...My 140 grains are 2.83, I have found the average seems to be 3.065 for the 175 grain. For my first time at my range, I used 3.07 and no problems after JJ opened mine as well.

Thanks!!!

 

[rookhawk]

Frantz, what is the COAL you are using with your 175 grain bullets for your 275 please? I see different information...My 140 grains are 2.83, I have found the average seems to be 3.065 for the 175 grain. For my first time at my range, I used 3.07 and no problems after JJ opened mine as well.

Thanks!!!

You really can't measure COAL to determine if its going to work well. You need a comparator that measures ogive from exhibit A to exhibit B. For accuracy in relation to jump off the lands, you need to know the bearing surface of the bullet in relation to one another.

An example of this at the extreme would be a NF or A-frame as a lead 160gr bullet versus say an all copper TTSX 160gr. Since copper is 22% larger (less dense) by volume, that copper bullet is going to fill a space roughly the size of a 198gr lead soft. Obviously, a gun throated to shoot a 140gr lead soft is not going to do very well with a 198gr-sized copper bullet that happens to weigh 160gr.

This is just personal bias so take it as opinion: Everything glorious about the 275 Rigby / 7x57 in the annals of big game hunting was based on its heavy-for-caliber bullets, controlled expansion, deep penetration, and extraordinary B.C.s. A lead-core bullet of stout design whether North Fork, A-Frame, Norma Oryx of the heaviest weight that shoots accurately is going to give you excellent results. I suspect a 150gr-160gr NF soft will shoot well out of the Rigby High Velocity throat.

 

[gcbailey]

I don't know about the new Highland Stalker rifles, but my 1927 .275 Rigby handled 175 grain bullets with no issues.

 

[rookhawk]

I don't know about the new Highland Stalker rifles, but my 1927 .275 Rigby handled 175 grain bullets with no issues.

Does your barrel say "Rigby High Velocity" on it? HV = 140gr, if it doesn't say that it was designed originally for the 173gr-175gr soft and 180gr solid.

 

[Wyatt Smith]

Seems to me the best course of action would’ve to have reamed to 7x57 specs to shoot any ammunition.
I bet it still shoots 120-140s just fine, I know my 7x57 does.

 

[gcbailey]

Does your barrel say "Rigby High Velocity" on it? HV = 140gr, if it doesn't say that it was designed originally for the 173gr-175gr soft and 180gr solid.

Oh, I didn't know there was a difference and assumed they were all made for 140 grains. Mine does say H.V. as does the original ledger, but it threw 175 grain bullets perfectly and took an impala, warthog, crocodile, and Gemsbok with ease.

 

[Rare Breed]

Seems to me the best course of action would’ve to have reamed to 7x57 specs to shoot any ammunition.
I bet it still shoots 120-140s just fine, I know my 7x57 does.

My 140 grains do cloverleaves easily. I need to tweak my loads slightly to get my 175 grains to do the same.

 

[Hunter-Habib]

Oh, I didn't know there was a difference and assumed they were all made for 140 grains. Mine does say H.V. as does the original ledger, but it threw 175 grain bullets perfectly and took an impala, warthog, crocodile, and Gemsbok with ease.

Many of these vintage .275 Rigby HV rifles were exported to the colonies and retailed through firms such as Manton & Co., RB Rodda & Co., Lyon & Lyon and Army & Navy.

These firms had in-house gunsmiths who would often ream the chambers & lengthen the throats on these rifles (upon request from the customers) in order to work properly with 173-177Gr bullets. The purpose of this, was to ensure that common 7x57mm Mauser ammunition would properly work in these rifles since specific kinds of ammunition was sometimes scarce in the colonies for up to several months at a time.

 

[gcbailey]

Many of these vintage .275 Rigby HV rifles were exported to the colonies and retailed through firms such as Manton & Co., RB Rodda & Co., Lyon & Lyon and Army & Navy.

These firms had in-house gunsmiths who would often ream the chambers & lengthen the throats on these rifles (upon request from the customers) in order to work properly with 173-177Gr bullets. The purpose of this, was to ensure that common 7x57mm Mauser ammunition would properly work in these rifles since specific kinds of ammunition was sometimes scarce in the colonies for up to several months at a time.

Just another reason why I love this group. I learn something new all the time.