Experiment to see if we can compensate for a burned out throat on a .243 by seating bullets long

[HandB]

My Tikka M55 in .243 is about 30 years old and has a burned out throat typical of an elderly .243, with loads of rifling missing for the first third of the barrel and huge jumps to the lands required when seating to manufacturer OALs. The throat is eroded so much that a typical tangent ogive boat tail bullet can't reach the lands without running out of case neck to grip the bullet. But Hornady SST 95gr bullets are long and skinny with a super pointy secant ogive and no boat tail. So they can be seated into the lands and still have enough length to be gripped by the full length of the case neck. I tried them with a 15th jump at 200yds with a five shot group and it cut the group size by more than a half (approx. 0.3MOA). This needs more testing but it looks like long skinny secant bullets are one way of eking out performance from am old .243 with a burned out throat.

 

[EMcC]

I don't know anything about adjusting bullets to suit a burnt out throat but several years ago I got hold of a .308 target rifle for peanuts because it had a burnt out throat
It was so long ago that I can't remember the rifle smith but he was at Bisley and what he did was take the chamber further in and as a result no more burnt out throat.
Perhaps that is an option for you if you have no luck any other way.

 

[HandB]

I don't know anything about adjusting bullets to suit a burnt out throat but several years ago I got hold of a .308 target rifle for peanuts because it had a burnt out throat
It was so long ago that I can't remember the rifle smith but he was at Bisley and what he did was take the chamber further in and as a result no more burnt out throat.
Perhaps that is an option for you if you have no luck any other way.

Thanks yes good point, setting the chamber back or even a full rebarrel would be a better solution. I will see how things go with this cheapo method for now, as I am on quite a small budget at the moment.

 

[Klenchblaize]

It’s interesting that this bullet still permits full case neck contact.

K

 

[HandB]

It’s interesting that this bullet still permits full case neck contact.

K

Yes the addition of a boat tail may be good for the aerodynamics of a bullet but it reduces how far out one can seat the bullet relative to a flat base bullet by about 2 or 3mm, which in this case is crucial for accuracy.

 

[plumber01]

I think looking through a bore scope can be scary. A friend at the range turned up with one, for a lit of a laugh we checked out some old 303 enfields, it looked horrible, even far newer guns can look marked. and with smoothing of the rifling. I'm sure more knowledgeable people here will inform us, but rifles also get coated with copper, this seems to fill in the groves, however its also a lubricant , and when you do a deep clean you remove a lot of it, then you find the rifle needs about 50 rounds through it to regain accuracy. Hence many shooters dont clean guns after every use, especially .22 rimfire rifles.
From experience you can stretch out your bullets, but shot out barrels deteriorate very quickly with use, and you may be ordering up a new barrel in the next 1000 rounds , however, its a great chance to think about barrel length, twist rate etc, and its like a new rifle again.

 

[dvbookshop]

My Tikka M55 in .243 is about 30 years old and has a burned out throat typical of an elderly .243, with loads of rifling missing for the first third of the barrel and huge jumps to the lands required when seating to manufacturer OALs. The throat is eroded so much that a typical tangent ogive boat tail bullet can't reach the lands without running out of case neck to grip the bullet. But Hornady SST 95gr bullets are long and skinny with a super pointy secant ogive and no boat tail. So they can be seated into the lands and still have enough length to be gripped by the full length of the case neck. I tried them with a 15th jump at 200yds with a five shot group and it cut the group size by more than a half (approx. 0.3MOA). This needs more testing but it looks like long skinny secant bullets are one way of eking out performance from am old .243 with a burned out throat.

Might be worth trying bullets with exposed lead at the base in case they expand into the rifling (or lack of it) better.

 

[1894]

My 243 became very worn after 250odd rounds of RL17 (on top of 1,600+ ‘ordinary’ rounds).
Seating way longer made it extremely accurate although copper fouling is bad enough I have to use JB.
I am seriously considering a Wyatt mag box to try to extend further when accuracy goes away again

 

[Druid]

A friend @Lampwick bought an almost shot out .303 which when tried with boat tail bullets was putting them through the target sideways at 25m!
Using flat base 150g bullets it shoots great.

 

[JTO]

Setting back the chamber won't double you barrel's life, I was told. Might as well think about a new barrel!

 

[alberta boy]

A friend @Lampwick bought an almost shot out .303 which when tried with boat tail bullets was putting them through the target sideways at 25m!
Using flat base 150g bullets it shoots great.

I've had the same results in a number of 303's , I've always got the best results with flat base bullets .

AB

 

[enfieldspares]

My Tikka M55 in .243 is about 30 years old and has a burned out throat typical of an elderly .243, with loads of rifling missing for the first third of the barrel and huge jumps to the lands required when seating to manufacturer OALs. The throat is eroded so much that a typical tangent ogive boat tail bullet can't reach the lands without running out of case neck to grip the bullet. But Hornady SST 95gr bullets are long and skinny with a super pointy secant ogive and no boat tail. So they can be seated into the lands and still have enough length to be gripped by the full length of the case neck. I tried them with a 15th jump at 200yds with a five shot group and it cut the group size by more than a half (approx. 0.3MOA). This needs more testing but it looks like long skinny secant bullets are one way of eking out performance from am old .243 with a burned out throat.

If and it is a BIG if there is enough length on the action AND enough thickness at the rear of the barrel you could make a 6mm-06 simply be running a chamber reamer into it.

I am no great fan of Chuck Hawks but here he is:

6mm-06

Now as to whether that's a "custom" aka bespoke 6mm-06 reamer or you just use a standard .243 Winchester and take it further towards the muzzle I don't know. For sure it'd probably be the cheapest option? Requiring ONLY re-chambering and then re-proof.

 

[HandB]

If and it is a BIG if there is enough length on the action AND enough thickness at the rear of the barrel you could make a 6mm-06 simply be running a chamber reamer into it.

I am no great fan of Chuck Hawks but here he is:

6mm-06

Now as to whether that's a "custom" aka bespoke 6mm-06 reamer or you just use a standard .243 Winchester and take it further towards the muzzle I don't know. For sure it'd probably be the cheapest option? Requiring ONLY re-chambering and then re-proof.

Thanks 6mm-06 sounds like a great cartridge, unfortunately the bore is damaged for about the first third of its length (missing chunks of rifling etc) so moving the throat forward to fit a 6mm-06 case would not move it ahead of the burned out area.